title: Sending reply to existing message using gmail api does not show conversation trail in the gmail inbox
body: <p>I'am using gmail rest api using Python. I construct the message using python built-in email library in the following way.</p>
  
  <pre><code>message=email.mime.multipart.MIMEMultipart('alternative')
  message['from'] = 'Satish &lt;satish@gmail.com&gt;'
  message['to'] = 'Satish1 &lt;satish1@gmail.com&gt;'
  message['subject'] = 'Same as reply to message's subject'
  raw_message = {'raw': base64.urlsafe_b64encode(message.as_string())}
  if reply_to:
      raw_message['threadId'] = reply_to  # thread id of existing conversation
  return raw_message
  </code></pre>
  
  <p><br>
  I sent this message using Gmail Rest Api like this:</p>
  
  <pre><code>users().messages().send(userId='me', body=raw_message).execute()
  </code></pre>
  
  <p>I'am getting this message as part of the thread which is fine. But unable to see conversation trail attached to the message. <br>
  [conversation trail is something attached with the message as <strong>...</strong> and when hovered it says <strong>show trimmed content</strong> ]</p>
  
  <p><br>
  Any help on this is appreciated.</p>
  
  <p>Thanks in Advance</p>