if np-plutoplus is negotation with a peer, all new
actions for that peer are dropped until the negotiation
is finished. they should be queued instead.
there is a simple queue mechanism in np-plutoplus, but
it is for starting the next action in a compound action
for the current peer. what is needed is a new queue for
pending actions. When the current action finishes, the
next pending one could be queued to begin.