title: Waiting for "finally" clause in PromiseKit to finish
body: <p>Currently I am using PromiseKit to chain a logic, which is like the following:</p>
  
  <pre><code>[NSURLConnection promise:rq1].then(^(id data1) {
      return [NSURLConnection promise:rq2];
  }).then(^(id data2) {
      return [NSURLConnection promise:rq3];
  }).then(^(id data3) {
      return [self promiseToDoSomeWorkOnData:data3];
  }).finally(^{
      [self cleanup];
  });
  </code></pre>
  
  <p>The problem that I am facing is that the method I call in the <code>finally</code> clause is asynchronous, but I have no way to chain the <code>finally</code> method together with the other promises so that any usage of the whole piece of code somewhere else waits also for the <code>finally</code> clause to finish before continuing to a next promise.</p>