If the user reads exactly the content length, rack expects the input to be closed.

lib/protocol/rack/input.rb

@@ -89,6 +89,13 @@ def read_next
 				if @body
 					# User's may forget to call #close...
 					if chunk = @body.read
+						# If the user reads exactly the content length, we close the stream automatically:
+						# https://github.com/socketry/async-http/issues/183
+						if @body.empty?
+							@body.close
+							@body = nil
+						end
+
 						return chunk
 					else
 						# So if we are at the end of the stream, we close it automatically:

test/protocol/rack/input.rb

@@ -52,6 +52,12 @@
 				expect(input.body).to be_nil
 			end
 
+			it "can read exactly the content length" do
+				expect(body).to receive(:close)
+
+				expect(input.read(sample_data.join.bytesize)).to be == sample_data.join
+			end
+
 			it "can read no input" do
 				expect(input.read(0)).to be == ""
 			end