title: Blur background behind dialog flutter?
body: <p>I want to achieve blur background behind dialog on <code>SimpleDialog</code> class. What I'm looking for is something similar to this, but for flutter.</p>
  <p><a href="https://github.com/nitiwari-dev/Blur-behind-alert-dialog" rel="noreferrer">Github Android project</a></p>
  <p><strong>EDIT:</strong>
  I already checked this question, but this is about the Dialog, I want to implement it on <code>SimpleDialog</code>.</p>