title: Clojure's equlivalent to a jQuery Deferred?
body: <p>Clojure has <code>promise</code>, <code>future</code>, <code>delay</code>, etc. but none are semantically similar to a Deferred object in jQuery.  They generally block if dereferenced before the value is available.  Deferred objects utilize callbacks.  What does Clojure (not ClojureScript) itself offer that is similar to a jQuery Deferred?  </p>