fix(tests): explicit yield in test_create_ssl_server_manual_connection_lost

tests/test_context.py

@@ -474,6 +474,11 @@ def close():
                 # send data
                 await self.loop.run_in_executor(None,
                                                 ssl_sock.send, b'hello')
+                # After gh-105836 run_in_executor may resolve without
+                # yielding. This is very noticeable when PYTHONASYNCIODEBUG
+                # is set. Hence, we yield explicitly so that the sent data
+                # can reach the SSL buffer before close/resume_reading.
+                await asyncio.sleep(0)
                 # schedule a proactive transport close which will trigger
                 # the flushing process to retrieve the remaining data
                 self.loop.call_soon(close)