I am looking here:
http://clojuredocs.org/clojure.core/release-pending-sends
It says:
Normally, actions sent directly or indirectly during another action
are held until the action completes (changes the agent's
state). This function can be used to dispatch any pending sent
actions
What it means is if you have nested actions, e.g.
(def a (agent 0))
(def b (agent 0))
(send a (fn [x] (send b inc) (inc x)))
So under normal circumstances, the inner send is placed on a queue until
the value of a is changed. This means we can guarantee that a will change
before b.
