Tag 7: the client sends a message for the queue of the running loop; the server opens the proxy’s /agent/enqueue and relays exactly one channel response, the fate of the message, when the fate is known.
The client opens this channel to place a message in the queue of the
running loop. The server opens /agent/enqueue
on the proxy with the message and relays the fate the proxy answers.
The request. The tag byte 7 followed by the message as JSON.
Request states its form.
The response. Exactly one channel response, sent when the fate
of the message is known, however long that takes, and the channel
response finish. Response
states the sequence.