title: How to get sendgrid batch email request callback when all mail processed.
body: <p>I am using Sendgrid to send email to our users</p>
  
  <p>To fulfill our requirement i am making a batch request by adding a category Id.</p>
  
  <p>I just want to call a functionality(update my email source).when sendgrid processed every email from requested batch.</p>
  
  <p>Is their any way to set a callback in a email request that sendgrid call a link when all the mail of a batch is processed.  </p>