Close asyncio.Streams explicitly (do not rely on GC)

Author: 1st1

asyncpg/connect_utils.py

@@ -610,7 +610,9 @@ async def _negotiate_ssl_connection(host, port, conn_factory, *, loop, ssl,
 
         sock = sock.dup()  # Must come before tr.close()
     finally:
-        tr.close()
+        writer.close()
+        if hasattr(writer, 'wait_closed'):
+            await writer.wait_closed()
 
     try:
         return await conn_factory(sock=sock)  # Must come after tr.close()

asyncpg/connection.py

@@ -1223,6 +1223,8 @@ async def _cancel(self, waiter):
                 waiter.set_result(None)
             if w is not None:
                 w.close()
+                if hasattr(w, 'wait_closed'):
+                    await w.wait_closed()
 
     def _cancel_current_command(self, waiter):
         self._cancellations.add(self._loop.create_task(self._cancel(waiter)))