permanently delete only one gmail message from a thread using a google script

Question

I want to permanently delete a Gmail message inside a thread already in the trash.

I merged a few scripts around there, so I can delay and track emails. It works by

Answer 1

i finally made it trough an http request:

function cleanUp2() {
  var threads = GmailApp.search("in:trash is:draft");
  Logger.log(threads.length);

  var userId = 'xxxxx@gmail.com';
  var options = {
   'method' : 'delete',
   'muteHttpExceptions': true
 };

  for (var i = 0; i < threads.length; i++) {
    var messages = threads[i].getMessages();
    Logger.log(messages.length);

    for (var j = 0; j < messages.length; j++){
      if (messages[j].isDraft()){
        Logger.log('id msg: ' + messages[j].getId());
        var url = 'https://www.googleapis.com/gmail/v1/users/' + userId + '/messages/' + messages[j].getId();
        var response = UrlFetchApp.fetch(url,options);
        Logger.log(response);            
      }    
    }
  }
}