try #1.

pymodbus/client/base.py

@@ -314,18 +314,20 @@ def connection_made(self, transport):
     async def close(self):  # pylint: disable=invalid-overridden-method
         """Close connection."""
         if self.transport:
+            _logger.debug("--> JAN: closing transport")
             self.transport.close()
+            _logger.debug("--> JAN: closed transport")
             while self.transport is not None:
-                if self.transport.is_closing():
-                    _logger.debug("Waiting for transport close.")
                 await asyncio.sleep(0.1)
+            _logger.debug("--> JAN: done transport")
         self._connected = False
 
     def connection_lost(self, reason):
         """Call when the connection is lost or closed.
 
         The argument is either an exception object or None
         """
+        _logger.debug("--> JAN connection_lost called!")
         self._connection_lost(reason)
 
         if self.factory: