Flush recv_buffer on cancellation

If asyncio.wait_for is cancelled by the caller we need to clean up
the recv_buffer as well.

We also need to guard self.response_future.set_result with a done()
check to prevent asyncio.exceptions.InvalidStateError: invalid state
errors.

Author: jameshilliard

pymodbus/transaction/transaction.py

@@ -153,6 +153,9 @@ async def execute(self, no_response_expected: bool, request: ModbusPDU) -> Modbu
                     return response
                 except asyncio.exceptions.TimeoutError:
                     count_retries += 1
+                except asyncio.exceptions.CancelledError:
+                    self.recv_buffer = b""
+                    raise
             if self.count_until_disconnect < 0:
                 self.connection_lost(asyncio.TimeoutError("Server not responding"))
                 raise ModbusIOException(
@@ -194,7 +197,8 @@ def callback_data(self, data: bytes, addr: tuple | None = None) -> int:
                     raise ModbusIOException(
                         f"ERROR: request ask for id={self.request_dev_id} but got id={pdu.dev_id}, CLOSING CONNECTION."
                     )
-                self.response_future.set_result(self.last_pdu)
+                if not self.response_future.done():
+                    self.response_future.set_result(self.last_pdu)
         return used_len
 
     def getNextTID(self) -> int: