Reduce Delays from Expect: 100-continue headers

To have Fiddler Classic return the 100-Continue header for a request:

1. Click Rules > Customize Rules....

2. Add the following function inside the Handlers class:

   static function OnPeekAtRequestHeaders(oSession: Session) {
      if (oSession.HTTPMethodIs("POST") && oSession.oRequest.headers.ExistsAndContains("Expect", "continue"))
      {
        if (null != oSession.oRequest.pipeClient)
        {
          oSession["ui-backcolor"] = "lightyellow";
          oSession.oRequest.headers.Remove("Expect");
          oSession.oRequest.pipeClient.Send(System.Text.Encoding.ASCII.GetBytes("HTTP/1.1 100 Continue\r\nServer: Fiddler\r\n\r\n"));
        }
      }
   }