title: Gmail API In-Reply-To not working(Google not handling on one side)
body: <p><strong>Problem:</strong> When Reply to email is sent via api then in receiver side it is showing as thread that contains two email messages(<strong>good on receivers side</strong>) but the sender has two different emails one in Inbox and one in Sent Mail(<strong>Problem in sender side</strong>).</p>
  
  <p><strong>for example:</strong> </p>
  
  <p>Email is sent from A to B. 
  Again B sends to A.</p>
  
  <p>here in api i am giving the previous email message-id in "In-Reply-To" and "References",(according to rfc822 format) here Google is handling that message-id on the A side but not on B side. A receives the message in a single thread as two messages but in B's account it is showing as two separate emails one in Inbox and one in sent.</p>
  
  <p><strong>Api used:</strong> </p>
  
  <p><a href="https://www.googleapis.com/upload/gmail/v1/users/me/messages/send?uploadType=multipart">https://www.googleapis.com/upload/gmail/v1/users/me/messages/send?uploadType=multipart</a>
  Content-Type: "message/rfc822; boundary=foo_bar_baz"</p>
  
  <p>request body is in rfc2822 format</p>