Add README for FFI crate

Author: ladvoc

livekit-ffi/Cargo.toml

@@ -5,6 +5,7 @@ edition = "2021"
 license = "Apache-2.0"
 description = "FFI interface for bindings in other languages"
 repository = "https://github.com/livekit/rust-sdks"
+readme = "README.md"
 
 [features]
 default = ["rustls-tls-native-roots"]

livekit-ffi/README.md

@@ -0,0 +1,9 @@
+# LiveKit FFI
+
+Foreign function interface (FFI) bindings for LiveKit, used to support the following client SDKs:
+
+- [Python](https://github.com/livekit/python-sdks)
+- [NodeJS](https://github.com/livekit/node-sdks)
+- [Unity](https://github.com/livekit/client-sdk-unity)
+
+This crate is compiled as dynamic library, allowing client languages to invoke APIs from the core [_livekit_](https://crates.io/crates/livekit) crate.