title: How to know when we popback to one through navigation flutter?
body: <p>Hi i m navigating from page 1 to page 2 in flutter.my question is when i navigated from page 1 to page 2 using:</p>
  <pre><code>Navigator.push()
  </code></pre>
  <p>Now i wanna pop back from page 2 to page one i want to know that how can i know from page 1 that i popback from page 2
  Using:</p>
  <pre><code>Navigator.pop()
  </code></pre>
  <p>Simply i wanna update page 1 when i pop back from page to but i dont know how to get to know that i navigated from page 2.</p>
  <p>I have a bloc that blongs to page 1 and i want to call a event when i popback from page 2 without passing page 1 bloc to page 2.</p>