title: Exchange Online Mail Queue
body: <p>Is it possible to call a web service when an email is sent by any user on O365 tenancy and the email message hits the outgoing queue? I would like to call a process when the email reaches queue and then the process will pick that message and do some processing and put it back in the queue. During this the email should never be sent unless the process has done its thing.</p>
  
  <p>Is this possible? I have found the APIs but I am confused if its possible to do exactly what I am after. Thanks</p>