Fix keepalive timeout task will not execute to close transport

uvicorn/_handlers/http.py

@@ -79,8 +79,7 @@ def retrieve_exception(task: asyncio.Task) -> None:
     # yet: all data that the client might have already sent since the connection has
     # been established is in the `_buffer`.
     data = reader._buffer  # type: ignore
-    if data:
-        protocol.data_received(data)
+    protocol.data_received(data)
 
     # Let the transport run in the background. When closed, this future will complete
     # and we'll exit here.

uvicorn/protocols/http/h11_impl.py

@@ -126,6 +126,11 @@ def _unset_keepalive_if_required(self):
 
     def data_received(self, data):
         self._unset_keepalive_if_required()
+        if data == b"":
+            self.timeout_keep_alive_task = self.loop.call_later(
+                self.timeout_keep_alive, self.timeout_keep_alive_handler
+            )
+            return
 
         self.conn.receive_data(data)
         self.handle_events()

uvicorn/protocols/http/httptools_impl.py

@@ -126,6 +126,11 @@ def _unset_keepalive_if_required(self):
 
     def data_received(self, data):
         self._unset_keepalive_if_required()
+        if data == b"":
+            self.timeout_keep_alive_task = self.loop.call_later(
+                self.timeout_keep_alive, self.timeout_keep_alive_handler
+            )
+            return
 
         try:
             self.parser.feed_data(data)