title: How to create and execute a Queue of Action<Task<bool>>
body: <p>I'm looking to create an asynchronous callback mechanism where interested parties can register one or more callback methods.</p>
  
  <p>I'd like to trigger and <code>await</code> completion of all the <code>Actions</code> in the queue and determine if any one of them has returned <code>true</code>.</p>
  
  <p>Would anyone have any suggestions as to existing libraries or patterns to achieve this?</p>