code: def enqueue(self, stanza, **kwargs):
          
          if not self.established_event.is_set():
              raise ConnectionError("stream is not ready")
  
          return self.stream._enqueue(stanza, **kwargs)
docs: Put a `stanza` in the internal transmission queue and return a token to
          track it.
  
          :param stanza: Stanza to send
          :type stanza: :class:`IQ`, :class:`Message` or :class:`Presence`
          :param kwargs: see :class:`StanzaToken`
          :raises ConnectionError: if the stream is not :attr:`established`
              yet.
          :return: token which tracks the stanza
          :rtype: :class:`StanzaToken`
  
          The `stanza` is enqueued in the active queue for transmission and will
          be sent on the next opportunity. The relative ordering of stanzas
          enqueued is always preserved.
  
          Return a fresh :class:`StanzaToken` instance which traks the progress
          of the transmission of the `stanza`. The `kwargs` are forwarded to the
          :class:`StanzaToken` constructor.
  
          This method calls :meth:`~.stanza.StanzaBase.autoset_id` on the stanza
          automatically.
  
          .. seealso::
  
             :meth:`send`
                for a more high-level way to send stanzas.
  
          .. versionchanged:: 0.10
  
              This method has been moved from
              :meth:`aioxmpp.stream.StanzaStream.enqueue`.