title: Asynchronously calling other method in sinatra
body: <p>I have following flow:</p>
  
  <pre><code>upload big file and send token
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  save uploaded file temporary
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  response that file was correctly uploaded
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  callback that checks is file is valid
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  after validation make http request to defined address with token and 
  validation result, delete temporary file
  </code></pre>
  
  <p>How is the best way to implement this in sinatra?</p>
  
  <p>Only one solution that I found is use something like this: <a href="https://github.com/pmamediagroup/sinatra_run_later" rel="nofollow">sinatra_run_later</a></p>
  
  <p>There is something else to handle this case?</p>