code: function PushMessage(id, message) {
      if(!id || id.trim() === '') {
          throw new Error('Please provide a message ID.');
      }
  
      this.id = id.trim();
      this.recipients = [];
  
      this.setMessage(message);
      this.setDeliveryMethod('notspecified');
  }
docs: Creates a new message that can be pushed to the Push Protocol Gateway. The PushMessage has a unique identifier
  to identify the message in the outside world. This identifier must be globaly unique. Therefore, the id is mostly
  constructed out of the company's url in combination with the name of the application and the timestamp. An example of
  the id could be com.company.myapp13254655416 where myapp is the name of the application.
  
  @param  {String} id      An identifier that should be unique around the world. Mostly a combination of the company's url and the timestamp.
  @param  {String} message The message that should be send to the Push Protocol Gateway.
  @throws {Error}          If no ID is specified.