title: How can Rails observers and callbacks be handled asynchronously (in a different thread)?
body: <p>Observers and Callbacks on Rails models operate on the same thread and block the request until they return. </p>
  
  <p>For example, if I have a Photo model and I queue a resizing job in the after_create callback or observer, the request doesn't finish until an entry is made in the queue (which can sometimes be slow if I am using Amazon SQS for queuing).</p>
  
  <p>Same holds true for Callbacks on Rails controllers. If I have to run maintenance like cache management or store analytics the request doesn't finish until the callback ends.</p>
  
  <p>Is there a Rails way to run the code inside a callback (Model or Controller) or observer in a different thread so the request isn't stalled?</p>