Number of asks awaiting a reply.
Posts a message and resolves with the remote handler's reply.
Stops listening and rejects every pending ask with a RemoteError (code: 'closed').
Posts a message. Resolves once the transport has accepted it; delivery is not acknowledged.
A Ref to an actor served on the other side of a Transport.
sendandaskbehave like their local counterparts; a handler error on the remote side rejectsaskwith a RemoteError.