title: Dropzone event before removing a file
body: <p>In <a href="https://www.dropzonejs.com/" rel="nofollow noreferrer">dropzone</a> we have a <code>removedFile</code> event, which is fired after file is removed. </p>
  
  <p>What I need is an event that is fired before file is removed, so that I can trigger removal from server and if it succeeds then will remove a file from dropzone, otherwise file from dropzone will not be removed and error message will be shown. </p>
  
  <p>Any idea ?</p>