code: function resolve( xhr, body, headers ) {
  	const e = new ProgressEvent( 'load' );
  	e.data = e.body = e.response = body;
  	e.headers = headers;
  	xhr.dispatchEvent( e );
  }
docs: Emits the "load" event on the `xhr`.
  
  @param {XMLHttpRequest} xhr
  @param {Object} body
  @private