Not thread-safe.

def _handle_human_connection_event(
        self,
        event: events.HumanConnectionEvent,
    ) -> None:
        """
        Not thread-safe.

        """
        for subscriber in self._human_connection_subscribers:
            try:
                subscriber(event)
            except Exception:
                LOG.exception(self._prefix_log_message(
                    f"failed to send human connection event {event} to "
                    f"subscriber {subscriber}"
                ))