code: def _report_replica_set_state(self, state, clean_server_name, replset_name):
          
          last_state = self._last_state_by_server.get(clean_server_name, -1)
          self._last_state_by_server[clean_server_name] = state
          if last_state != state and last_state != -1:
              return self.create_event(last_state, state, clean_server_name, replset_name)
docs: Report the member's replica set state
          * Submit a service check.
          * Create an event on state change.