code: async def on_open_async(self):
          
          _opened_ok = False
          _retry_count = 0
          while (not _opened_ok) and (_retry_count < 5):
              try:
                  await self.open_clients_async()
                  _opened_ok = True
              except Exception as err:  # pylint: disable=broad-except
                  _logger.warning(
                      "%r,%r PartitionPumpWarning: Failure creating client or receiver, retrying: %r",
                      self.host.guid, self.partition_context.partition_id, err)
                  last_exception = err
                  _retry_count += 1
  
          if not _opened_ok:
              await self.processor.process_error_async(self.partition_context, last_exception)
              self.set_pump_status("OpenFailed")
  
          if self.pump_status == "Opening":
              loop = asyncio.get_event_loop()
              self.set_pump_status("Running")
              await self.eh_client.run_async()
              self.running = loop.create_task(self.partition_receiver.run())
  
          if self.pump_status in ["OpenFailed", "Errored"]:
              self.set_pump_status("Closing")
              await self.clean_up_clients_async()
              self.set_pump_status("Closed")
docs: Eventhub Override for on_open_async.