message <span class="message">Request</span>
{
  required <span class="number">uint32</span> requestID  = 1; 
  required <span class="number">uint32</span> resourceID = 2; 
  required <span class="number">uint32</span> windowID   = 3; 
  optional <span class="number">uint32</span> frameID    = 4; 
  optional <span class="number">uint32</span> documentID = 5; 
  required <span class="string">string</span> url        = 6; 
  <span class="comment">/** 
   * Milliseconds since Unix epoch.
   */</span>
  required <span class="number">double</span> time       = 7; 
  required <span class="string">string</span> method     = 8; 
}
