diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 6fc4d8db..044b8c5f 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -44,6 +44,9 @@ jobs:
     runs-on: macos-13
     steps:
       - uses: actions/checkout@v4
+      - name: Select Xcode version
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-13-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_15.0.app
       - uses: bufbuild/buf-setup-action@v1.28.0
         with:
           github_token: ${{ github.token }}
diff --git a/.swiftlint.yml b/.swiftlint.yml
index b83c8f94..b4100727 100644
--- a/.swiftlint.yml
+++ b/.swiftlint.yml
@@ -4,7 +4,7 @@ included:
   - Plugins
   - Tests
 excluded:
-  - Libraries/Connect/Implementation/Generated
+  - Libraries/Connect/Internal/Generated
   - Tests/ConnectLibraryTests/Generated
 disabled_rules:
   - blanket_disable_command
diff --git a/Libraries/Connect/Implementation/Generated/grpc/status/v1/status.pb.swift b/Libraries/Connect/Internal/Generated/grpc/status/v1/status.pb.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Generated/grpc/status/v1/status.pb.swift
rename to Libraries/Connect/Internal/Generated/grpc/status/v1/status.pb.swift
diff --git a/Libraries/Connect/Implementation/Interceptors/ConnectInterceptor.swift b/Libraries/Connect/Internal/Interceptors/ConnectInterceptor.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Interceptors/ConnectInterceptor.swift
rename to Libraries/Connect/Internal/Interceptors/ConnectInterceptor.swift
diff --git a/Libraries/Connect/Implementation/Interceptors/GRPCWebInterceptor.swift b/Libraries/Connect/Internal/Interceptors/GRPCWebInterceptor.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Interceptors/GRPCWebInterceptor.swift
rename to Libraries/Connect/Internal/Interceptors/GRPCWebInterceptor.swift
diff --git a/Libraries/Connect/Implementation/Interceptors/InterceptorChain.swift b/Libraries/Connect/Internal/Interceptors/InterceptorChain.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Interceptors/InterceptorChain.swift
rename to Libraries/Connect/Internal/Interceptors/InterceptorChain.swift
diff --git a/Libraries/Connect/Implementation/Lock.swift b/Libraries/Connect/Internal/Locks/Lock.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Lock.swift
rename to Libraries/Connect/Internal/Locks/Lock.swift
diff --git a/Libraries/Connect/Implementation/Locked.swift b/Libraries/Connect/Internal/Locks/Locked.swift
similarity index 88%
rename from Libraries/Connect/Implementation/Locked.swift
rename to Libraries/Connect/Internal/Locks/Locked.swift
index 393a73c5..8219353a 100644
--- a/Libraries/Connect/Implementation/Locked.swift
+++ b/Libraries/Connect/Internal/Locks/Locked.swift
@@ -16,12 +16,12 @@ import Foundation
 
 /// Class containing an internal lock which can be used to ensure thread-safe access to an
 /// underlying value. Conforms to `Sendable`, making it accessible from `@Sendable` closures.
-public final class Locked<T>: @unchecked Sendable {
+final class Locked<T>: @unchecked Sendable {
     private let lock = Lock()
     private var wrappedValue: T
 
     /// Thread-safe access to the underlying value.
-    public var value: T {
+    var value: T {
         get { self.lock.perform { self.wrappedValue } }
         set { self.lock.perform { self.wrappedValue = newValue } }
     }
@@ -29,13 +29,13 @@ public final class Locked<T>: @unchecked Sendable {
     /// Perform an action with the underlying value, potentially updating that value.
     ///
     /// - parameter action: Closure to perform with the underlying value.
-    public func perform(action: @escaping (inout T) -> Void) {
+    func perform(action: @escaping (inout T) -> Void) {
         self.lock.perform {
             action(&self.wrappedValue)
         }
     }
 
-    public init(_ value: T) {
+    init(_ value: T) {
         self.wrappedValue = value
     }
 }
diff --git a/Libraries/Connect/Implementation/Streaming/BidirectionalAsyncStream.swift b/Libraries/Connect/Internal/Streaming/BidirectionalAsyncStream.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Streaming/BidirectionalAsyncStream.swift
rename to Libraries/Connect/Internal/Streaming/BidirectionalAsyncStream.swift
diff --git a/Libraries/Connect/Implementation/Streaming/BidirectionalStream.swift b/Libraries/Connect/Internal/Streaming/BidirectionalStream.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Streaming/BidirectionalStream.swift
rename to Libraries/Connect/Internal/Streaming/BidirectionalStream.swift
diff --git a/Libraries/Connect/Interfaces/ConnectEndStreamResponse.swift b/Libraries/Connect/Internal/Streaming/ConnectEndStreamResponse.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/ConnectEndStreamResponse.swift
rename to Libraries/Connect/Internal/Streaming/ConnectEndStreamResponse.swift
diff --git a/Libraries/Connect/Implementation/Streaming/ServerOnlyAsyncStream.swift b/Libraries/Connect/Internal/Streaming/ServerOnlyAsyncStream.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Streaming/ServerOnlyAsyncStream.swift
rename to Libraries/Connect/Internal/Streaming/ServerOnlyAsyncStream.swift
diff --git a/Libraries/Connect/Implementation/Streaming/ServerOnlyStream.swift b/Libraries/Connect/Internal/Streaming/ServerOnlyStream.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Streaming/ServerOnlyStream.swift
rename to Libraries/Connect/Internal/Streaming/ServerOnlyStream.swift
diff --git a/Libraries/Connect/Implementation/Streaming/URLSessionStream.swift b/Libraries/Connect/Internal/Streaming/URLSessionStream.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Streaming/URLSessionStream.swift
rename to Libraries/Connect/Internal/Streaming/URLSessionStream.swift
diff --git a/Libraries/Connect/Implementation/UnaryAsyncWrapper.swift b/Libraries/Connect/Internal/Unary/UnaryAsyncWrapper.swift
similarity index 100%
rename from Libraries/Connect/Implementation/UnaryAsyncWrapper.swift
rename to Libraries/Connect/Internal/Unary/UnaryAsyncWrapper.swift
diff --git a/Libraries/Connect/Implementation/GRPC/ConnectError+GRPC.swift b/Libraries/Connect/PackageInternal/ConnectError+GRPC.swift
similarity index 89%
rename from Libraries/Connect/Implementation/GRPC/ConnectError+GRPC.swift
rename to Libraries/Connect/PackageInternal/ConnectError+GRPC.swift
index 7df94125..a233b5fa 100644
--- a/Libraries/Connect/Implementation/GRPC/ConnectError+GRPC.swift
+++ b/Libraries/Connect/PackageInternal/ConnectError+GRPC.swift
@@ -21,7 +21,17 @@ extension ConnectError {
     /// - parameter code: The status code received from the server.
     ///
     /// - returns: An error, if the status indicated an error.
-    public static func fromGRPCTrailers(_ trailers: Trailers, code: Code) -> Self? {
+#if COCOAPODS // ConnectNIO is unavailable from CocoaPods, so this can be internal.
+    static func fromGRPCTrailers(_ trailers: Trailers, code: Code) -> Self? {
+        return self._fromGRPCTrailers(trailers, code: code)
+    }
+#else
+    package static func fromGRPCTrailers(_ trailers: Trailers, code: Code) -> Self? {
+        return self._fromGRPCTrailers(trailers, code: code)
+    }
+#endif
+
+    private static func _fromGRPCTrailers(_ trailers: Trailers, code: Code) -> Self? {
         if code == .ok {
             return nil
         }
diff --git a/Libraries/Connect/Implementation/Codecs/Envelope.swift b/Libraries/Connect/PackageInternal/Envelope.swift
similarity index 93%
rename from Libraries/Connect/Implementation/Codecs/Envelope.swift
rename to Libraries/Connect/PackageInternal/Envelope.swift
index 952246ea..f222d4ad 100644
--- a/Libraries/Connect/Implementation/Codecs/Envelope.swift
+++ b/Libraries/Connect/PackageInternal/Envelope.swift
@@ -16,39 +16,10 @@ import Foundation
 import SwiftProtobuf
 
 /// Provides functionality for packing and unpacking (headers and length prefixed) messages.
+///
+/// This API is not considered part of Connect's public interface and is subject to change.
+/// TODO: Make this `package` instead of `public` if/when CocoaPods support is dropped.
 public enum Envelope {
-    public enum Error: Swift.Error {
-        case missingExpectedCompressionPool
-    }
-
-    /// The total number of bytes that will prefix a message.
-    public static var prefixLength: Int {
-        return 5 // Header flags (1 byte) + message length (4 bytes)
-    }
-
-    /// Computes the length of the message contained by a packed chunk of data.
-    /// A packed chunk in this context refers to prefixed message data.
-    ///
-    /// Compliant with Connect streams: https://connectrpc.com/docs/protocol/#streaming-request
-    /// And gRPC: https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#responses
-    ///
-    /// - parameter data: The packed data from which to determine the enveloped message's size.
-    ///
-    /// - returns: The length of the next expected message in the packed data. If multiple chunks
-    ///            are specified, this will return the length of the first. Returns -1 if there is
-    ///            not enough prefix data to determine the message length.
-    public static func messageLength(forPackedData data: Data) -> Int {
-        guard data.count >= self.prefixLength else {
-            return -1
-        }
-
-        // Skip header flags (1 byte) and determine the message length (next 4 bytes, big-endian)
-        var messageLength: UInt32 = 0
-        (data[1...4] as NSData).getBytes(&messageLength, length: 4)
-        messageLength = UInt32(bigEndian: messageLength)
-        return Int(messageLength)
-    }
-
     /// Packs a message into an "envelope", adding required header bytes and optionally
     /// applying compression.
     ///
@@ -112,6 +83,40 @@ public enum Envelope {
         }
     }
 
+    // MARK: - Internal
+
+    enum Error: Swift.Error {
+        case missingExpectedCompressionPool
+    }
+
+    /// The total number of bytes that will prefix a message.
+    static var prefixLength: Int {
+        return 5 // Header flags (1 byte) + message length (4 bytes)
+    }
+
+    /// Computes the length of the message contained by a packed chunk of data.
+    /// A packed chunk in this context refers to prefixed message data.
+    ///
+    /// Compliant with Connect streams: https://connectrpc.com/docs/protocol/#streaming-request
+    /// And gRPC: https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#responses
+    ///
+    /// - parameter data: The packed data from which to determine the enveloped message's size.
+    ///
+    /// - returns: The length of the next expected message in the packed data. If multiple chunks
+    ///            are specified, this will return the length of the first. Returns -1 if there is
+    ///            not enough prefix data to determine the message length.
+    static func messageLength(forPackedData data: Data) -> Int {
+        guard data.count >= self.prefixLength else {
+            return -1
+        }
+
+        // Skip header flags (1 byte) and determine the message length (next 4 bytes, big-endian)
+        var messageLength: UInt32 = 0
+        (data[1...4] as NSData).getBytes(&messageLength, length: 4)
+        messageLength = UInt32(bigEndian: messageLength)
+        return Int(messageLength)
+    }
+
     // MARK: - Private
 
     private static func write(lengthOf message: Data, to buffer: inout Data) {
diff --git a/Libraries/Connect/Implementation/GRPC/Headers+GRPC.swift b/Libraries/Connect/PackageInternal/Headers+GRPC.swift
similarity index 79%
rename from Libraries/Connect/Implementation/GRPC/Headers+GRPC.swift
rename to Libraries/Connect/PackageInternal/Headers+GRPC.swift
index 4ad0424e..fbf0d8ec 100644
--- a/Libraries/Connect/Implementation/GRPC/Headers+GRPC.swift
+++ b/Libraries/Connect/PackageInternal/Headers+GRPC.swift
@@ -22,7 +22,17 @@ extension Headers {
     /// - parameter grpcWeb: Should be true if using gRPC-Web, false if gRPC.
     ///
     /// - returns: A set of updated headers.
-    public func addingGRPCHeaders(using config: ProtocolClientConfig, grpcWeb: Bool) -> Self {
+#if COCOAPODS // ConnectNIO is unavailable from CocoaPods, so this can be internal.
+    func addingGRPCHeaders(using config: ProtocolClientConfig, grpcWeb: Bool) -> Self {
+        return self._addingGRPCHeaders(using: config, grpcWeb: grpcWeb)
+    }
+#else
+    package func addingGRPCHeaders(using config: ProtocolClientConfig, grpcWeb: Bool) -> Self {
+        return self._addingGRPCHeaders(using: config, grpcWeb: grpcWeb)
+    }
+#endif
+
+    private func _addingGRPCHeaders(using config: ProtocolClientConfig, grpcWeb: Bool) -> Self {
         var headers = self
         headers[HeaderConstants.grpcAcceptEncoding] = config
             .acceptCompressionPoolNames()
diff --git a/Libraries/Connect/Implementation/GRPC/Trailers+GRPC.swift b/Libraries/Connect/PackageInternal/Trailers+gRPC.swift
similarity index 75%
rename from Libraries/Connect/Implementation/GRPC/Trailers+GRPC.swift
rename to Libraries/Connect/PackageInternal/Trailers+gRPC.swift
index 616ce71d..de718861 100644
--- a/Libraries/Connect/Implementation/GRPC/Trailers+GRPC.swift
+++ b/Libraries/Connect/PackageInternal/Trailers+gRPC.swift
@@ -16,7 +16,17 @@ extension Trailers {
     /// Identifies the status code from gRPC and gRPC-Web trailers.
     ///
     /// - returns: The gRPC status code, if specified.
-    public func grpcStatus() -> Code? {
+#if COCOAPODS // ConnectNIO is unavailable from CocoaPods, so this can be internal.
+    func grpcStatus() -> Code? {
+        return self._grpcStatus()
+    }
+#else
+    package func grpcStatus() -> Code? {
+        return self._grpcStatus()
+    }
+#endif
+
+    private func _grpcStatus() -> Code? {
         return self[HeaderConstants.grpcStatus]?
             .first
             .flatMap(Int.init)
diff --git a/Libraries/Connect/Implementation/ProtocolClient.swift b/Libraries/Connect/Public/Implementation/Clients/ProtocolClient.swift
similarity index 100%
rename from Libraries/Connect/Implementation/ProtocolClient.swift
rename to Libraries/Connect/Public/Implementation/Clients/ProtocolClient.swift
diff --git a/Libraries/Connect/Implementation/URLSessionHTTPClient.swift b/Libraries/Connect/Public/Implementation/Clients/URLSessionHTTPClient.swift
similarity index 100%
rename from Libraries/Connect/Implementation/URLSessionHTTPClient.swift
rename to Libraries/Connect/Public/Implementation/Clients/URLSessionHTTPClient.swift
diff --git a/Libraries/Connect/Implementation/Codecs/JSONCodec.swift b/Libraries/Connect/Public/Implementation/Codecs/JSONCodec.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Codecs/JSONCodec.swift
rename to Libraries/Connect/Public/Implementation/Codecs/JSONCodec.swift
diff --git a/Libraries/Connect/Implementation/Codecs/ProtoCodec.swift b/Libraries/Connect/Public/Implementation/Codecs/ProtoCodec.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Codecs/ProtoCodec.swift
rename to Libraries/Connect/Public/Implementation/Codecs/ProtoCodec.swift
diff --git a/Libraries/Connect/Implementation/Compression/GzipCompressionPool.swift b/Libraries/Connect/Public/Implementation/Compression/GzipCompressionPool.swift
similarity index 100%
rename from Libraries/Connect/Implementation/Compression/GzipCompressionPool.swift
rename to Libraries/Connect/Public/Implementation/Compression/GzipCompressionPool.swift
diff --git a/Libraries/Connect/Interfaces/Cancelable.swift b/Libraries/Connect/Public/Interfaces/Cancelable.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Cancelable.swift
rename to Libraries/Connect/Public/Interfaces/Cancelable.swift
diff --git a/Libraries/Connect/Interfaces/Code.swift b/Libraries/Connect/Public/Interfaces/Code.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Code.swift
rename to Libraries/Connect/Public/Interfaces/Code.swift
diff --git a/Libraries/Connect/Interfaces/Codec.swift b/Libraries/Connect/Public/Interfaces/Codec.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Codec.swift
rename to Libraries/Connect/Public/Interfaces/Codec.swift
diff --git a/Libraries/Connect/Interfaces/CompressionPool.swift b/Libraries/Connect/Public/Interfaces/CompressionPool.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/CompressionPool.swift
rename to Libraries/Connect/Public/Interfaces/CompressionPool.swift
diff --git a/Libraries/Connect/Interfaces/ConnectError.swift b/Libraries/Connect/Public/Interfaces/ConnectError.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/ConnectError.swift
rename to Libraries/Connect/Public/Interfaces/ConnectError.swift
diff --git a/Libraries/Connect/Interfaces/HTTPClientInterface.swift b/Libraries/Connect/Public/Interfaces/HTTPClientInterface.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/HTTPClientInterface.swift
rename to Libraries/Connect/Public/Interfaces/HTTPClientInterface.swift
diff --git a/Libraries/Connect/Interfaces/HTTPMethod.swift b/Libraries/Connect/Public/Interfaces/HTTPMethod.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/HTTPMethod.swift
rename to Libraries/Connect/Public/Interfaces/HTTPMethod.swift
diff --git a/Libraries/Connect/Interfaces/HTTPMetrics.swift b/Libraries/Connect/Public/Interfaces/HTTPMetrics.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/HTTPMetrics.swift
rename to Libraries/Connect/Public/Interfaces/HTTPMetrics.swift
diff --git a/Libraries/Connect/Interfaces/HTTPRequest.swift b/Libraries/Connect/Public/Interfaces/HTTPRequest.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/HTTPRequest.swift
rename to Libraries/Connect/Public/Interfaces/HTTPRequest.swift
diff --git a/Libraries/Connect/Interfaces/HTTPResponse.swift b/Libraries/Connect/Public/Interfaces/HTTPResponse.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/HTTPResponse.swift
rename to Libraries/Connect/Public/Interfaces/HTTPResponse.swift
diff --git a/Libraries/Connect/Interfaces/HeaderConstants.swift b/Libraries/Connect/Public/Interfaces/HeaderConstants.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/HeaderConstants.swift
rename to Libraries/Connect/Public/Interfaces/HeaderConstants.swift
diff --git a/Libraries/Connect/Interfaces/Headers.swift b/Libraries/Connect/Public/Interfaces/Headers.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Headers.swift
rename to Libraries/Connect/Public/Interfaces/Headers.swift
diff --git a/Libraries/Connect/Interfaces/IdempotencyLevel.swift b/Libraries/Connect/Public/Interfaces/IdempotencyLevel.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/IdempotencyLevel.swift
rename to Libraries/Connect/Public/Interfaces/IdempotencyLevel.swift
diff --git a/Libraries/Connect/Interfaces/Interceptors/Interceptor.swift b/Libraries/Connect/Public/Interfaces/Interceptors/Interceptor.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Interceptors/Interceptor.swift
rename to Libraries/Connect/Public/Interfaces/Interceptors/Interceptor.swift
diff --git a/Libraries/Connect/Interfaces/Interceptors/InterceptorFactory.swift b/Libraries/Connect/Public/Interfaces/Interceptors/InterceptorFactory.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Interceptors/InterceptorFactory.swift
rename to Libraries/Connect/Public/Interfaces/Interceptors/InterceptorFactory.swift
diff --git a/Libraries/Connect/Interfaces/Interceptors/StreamInterceptor.swift b/Libraries/Connect/Public/Interfaces/Interceptors/StreamInterceptor.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Interceptors/StreamInterceptor.swift
rename to Libraries/Connect/Public/Interfaces/Interceptors/StreamInterceptor.swift
diff --git a/Libraries/Connect/Interfaces/Interceptors/UnaryInterceptor.swift b/Libraries/Connect/Public/Interfaces/Interceptors/UnaryInterceptor.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Interceptors/UnaryInterceptor.swift
rename to Libraries/Connect/Public/Interfaces/Interceptors/UnaryInterceptor.swift
diff --git a/Libraries/Connect/Interfaces/MethodSpec.swift b/Libraries/Connect/Public/Interfaces/MethodSpec.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/MethodSpec.swift
rename to Libraries/Connect/Public/Interfaces/MethodSpec.swift
diff --git a/Libraries/Connect/Interfaces/NetworkProtocol.swift b/Libraries/Connect/Public/Interfaces/NetworkProtocol.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/NetworkProtocol.swift
rename to Libraries/Connect/Public/Interfaces/NetworkProtocol.swift
diff --git a/Libraries/Connect/Interfaces/ProtobufMessage.swift b/Libraries/Connect/Public/Interfaces/ProtobufMessage.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/ProtobufMessage.swift
rename to Libraries/Connect/Public/Interfaces/ProtobufMessage.swift
diff --git a/Libraries/Connect/Implementation/ProtocolClientConfig.swift b/Libraries/Connect/Public/Interfaces/ProtocolClientConfig.swift
similarity index 100%
rename from Libraries/Connect/Implementation/ProtocolClientConfig.swift
rename to Libraries/Connect/Public/Interfaces/ProtocolClientConfig.swift
diff --git a/Libraries/Connect/Interfaces/ProtocolClientInterface.swift b/Libraries/Connect/Public/Interfaces/ProtocolClientInterface.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/ProtocolClientInterface.swift
rename to Libraries/Connect/Public/Interfaces/ProtocolClientInterface.swift
diff --git a/Libraries/Connect/Interfaces/ResponseMessage.swift b/Libraries/Connect/Public/Interfaces/ResponseMessage.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/ResponseMessage.swift
rename to Libraries/Connect/Public/Interfaces/ResponseMessage.swift
diff --git a/Libraries/Connect/Interfaces/Streams/BidirectionalAsyncStreamInterface.swift b/Libraries/Connect/Public/Interfaces/Streaming/AsyncAwait/BidirectionalAsyncStreamInterface.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Streams/BidirectionalAsyncStreamInterface.swift
rename to Libraries/Connect/Public/Interfaces/Streaming/AsyncAwait/BidirectionalAsyncStreamInterface.swift
diff --git a/Libraries/Connect/Interfaces/Streams/ClientOnlyAsyncStreamInterface.swift b/Libraries/Connect/Public/Interfaces/Streaming/AsyncAwait/ClientOnlyAsyncStreamInterface.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Streams/ClientOnlyAsyncStreamInterface.swift
rename to Libraries/Connect/Public/Interfaces/Streaming/AsyncAwait/ClientOnlyAsyncStreamInterface.swift
diff --git a/Libraries/Connect/Interfaces/Streams/ServerOnlyAsyncStreamInterface.swift b/Libraries/Connect/Public/Interfaces/Streaming/AsyncAwait/ServerOnlyAsyncStreamInterface.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Streams/ServerOnlyAsyncStreamInterface.swift
rename to Libraries/Connect/Public/Interfaces/Streaming/AsyncAwait/ServerOnlyAsyncStreamInterface.swift
diff --git a/Libraries/Connect/Interfaces/Streams/BidirectionalStreamInterface.swift b/Libraries/Connect/Public/Interfaces/Streaming/Callbacks/BidirectionalStreamInterface.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Streams/BidirectionalStreamInterface.swift
rename to Libraries/Connect/Public/Interfaces/Streaming/Callbacks/BidirectionalStreamInterface.swift
diff --git a/Libraries/Connect/Interfaces/Streams/ClientOnlyStreamInterface.swift b/Libraries/Connect/Public/Interfaces/Streaming/Callbacks/ClientOnlyStreamInterface.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Streams/ClientOnlyStreamInterface.swift
rename to Libraries/Connect/Public/Interfaces/Streaming/Callbacks/ClientOnlyStreamInterface.swift
diff --git a/Libraries/Connect/Interfaces/Streams/RequestCallbacks.swift b/Libraries/Connect/Public/Interfaces/Streaming/Callbacks/RequestCallbacks.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Streams/RequestCallbacks.swift
rename to Libraries/Connect/Public/Interfaces/Streaming/Callbacks/RequestCallbacks.swift
diff --git a/Libraries/Connect/Interfaces/Streams/ResponseCallbacks.swift b/Libraries/Connect/Public/Interfaces/Streaming/Callbacks/ResponseCallbacks.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Streams/ResponseCallbacks.swift
rename to Libraries/Connect/Public/Interfaces/Streaming/Callbacks/ResponseCallbacks.swift
diff --git a/Libraries/Connect/Interfaces/Streams/ServerOnlyStreamInterface.swift b/Libraries/Connect/Public/Interfaces/Streaming/Callbacks/ServerOnlyStreamInterface.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Streams/ServerOnlyStreamInterface.swift
rename to Libraries/Connect/Public/Interfaces/Streaming/Callbacks/ServerOnlyStreamInterface.swift
diff --git a/Libraries/Connect/Interfaces/Streams/StreamResult.swift b/Libraries/Connect/Public/Interfaces/Streaming/StreamResult.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Streams/StreamResult.swift
rename to Libraries/Connect/Public/Interfaces/Streaming/StreamResult.swift
diff --git a/Libraries/Connect/Interfaces/Trailers.swift b/Libraries/Connect/Public/Interfaces/Trailers.swift
similarity index 100%
rename from Libraries/Connect/Interfaces/Trailers.swift
rename to Libraries/Connect/Public/Interfaces/Trailers.swift
diff --git a/Libraries/Connect/buf.gen.yaml b/Libraries/Connect/buf.gen.yaml
index d6a057bc..4c79ffda 100644
--- a/Libraries/Connect/buf.gen.yaml
+++ b/Libraries/Connect/buf.gen.yaml
@@ -2,4 +2,4 @@ version: v1
 plugins:
   - plugin: buf.build/apple/swift:v1.25.1
     opt: Visibility=Internal
-    out: ./Implementation/Generated
+    out: ./Internal/Generated
diff --git a/Libraries/ConnectNIO/Internal/GRPCInterceptor.swift b/Libraries/ConnectNIO/Internal/GRPCInterceptor.swift
index 9fd05302..006f8839 100644
--- a/Libraries/ConnectNIO/Internal/GRPCInterceptor.swift
+++ b/Libraries/ConnectNIO/Internal/GRPCInterceptor.swift
@@ -14,6 +14,7 @@
 
 import Connect
 import Foundation
+import NIOConcurrencyHelpers
 
 /// Implementation of the gRPC protocol as an interceptor.
 /// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md
@@ -186,3 +187,18 @@ extension GRPCInterceptor: StreamInterceptor {
         }
     }
 }
+
+private final class Locked<T>: @unchecked Sendable {
+    private let lock = NIOLock()
+    private var wrappedValue: T
+
+    /// Thread-safe access to the underlying value.
+    var value: T {
+        get { self.lock.withLock { self.wrappedValue } }
+        set { self.lock.withLock { self.wrappedValue = newValue } }
+    }
+
+    init(_ value: T) {
+        self.wrappedValue = value
+    }
+}
diff --git a/Makefile b/Makefile
index eed2f1c2..64e04f78 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,7 @@ LICENSE_HEADER_VERSION := v1.12.0
 LICENSE_IGNORE := -e Package.swift \
     -e $(BIN)\/ \
     -e Examples/ElizaSharedSources/GeneratedSources\/ \
-    -e Libraries/Connect/Implementation/Generated\/ \
+    -e Libraries/Connect/Internal/Generated\/ \
     -e Tests/ConnectLibraryTests/proto/grpc\/ \
     -e Tests/ConnectLibraryTests/Generated\/
 
diff --git a/Package.swift b/Package.swift
index 092d450a..c88f6ecb 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.6
+// swift-tools-version:5.9
 
 // Copyright 2022-2023 Buf Technologies, Inc.
 //
@@ -16,8 +16,10 @@
 
 import PackageDescription
 
+private let packageName = "Connect"
+
 let package = Package(
-    name: "Connect",
+    name: packageName,
     platforms: [
         .iOS(.v12),
         .macOS(.v10_15),
@@ -75,6 +77,9 @@ let package = Package(
                 "buf.work.yaml",
                 "proto",
                 "README.md",
+            ],
+            swiftSettings: [
+                .unsafeFlags(["-package-name", packageName])
             ]
         ),
         .testTarget(
@@ -104,6 +109,9 @@ let package = Package(
             path: "Libraries/ConnectMocks",
             exclude: [
                 "README.md",
+            ],
+            swiftSettings: [
+                .unsafeFlags(["-package-name", packageName])
             ]
         ),
         .executableTarget(
@@ -129,6 +137,9 @@ let package = Package(
             path: "Libraries/ConnectNIO",
             exclude: [
                 "README.md",
+            ],
+            swiftSettings: [
+                .unsafeFlags(["-package-name", packageName])
             ]
         ),
         .target(
diff --git a/Tests/ConnectLibraryTests/ConnectConformance/CallbackConformanceTests.swift b/Tests/ConnectLibraryTests/ConnectConformance/CallbackConformanceTests.swift
index 1f84d521..2900fd49 100644
--- a/Tests/ConnectLibraryTests/ConnectConformance/CallbackConformanceTests.swift
+++ b/Tests/ConnectLibraryTests/ConnectConformance/CallbackConformanceTests.swift
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import Connect
+@testable import Connect
 import Foundation
 import SwiftProtobuf
 import XCTest
diff --git a/Tests/ConnectLibraryTests/ConnectMocksTests/ConnectMocksTests.swift b/Tests/ConnectLibraryTests/ConnectMocksTests/ConnectMocksTests.swift
index 30c30028..2962c95f 100644
--- a/Tests/ConnectLibraryTests/ConnectMocksTests/ConnectMocksTests.swift
+++ b/Tests/ConnectLibraryTests/ConnectMocksTests/ConnectMocksTests.swift
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import Connect
+@testable import Connect
 import ConnectMocks
 import SwiftProtobuf
 import XCTest
diff --git a/Tests/ConnectLibraryTests/ConnectTests/EnvelopeTests.swift b/Tests/ConnectLibraryTests/ConnectTests/EnvelopeTests.swift
index be693d09..b0a784d0 100644
--- a/Tests/ConnectLibraryTests/ConnectTests/EnvelopeTests.swift
+++ b/Tests/ConnectLibraryTests/ConnectTests/EnvelopeTests.swift
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import Connect
+@testable import Connect
 import XCTest
 
 final class EnvelopeTests: XCTestCase {