loadAsync( url, onProgress ) {

		const scope = this;

		return new Promise( function ( resolve, reject ) {

			scope.load( url, resolve, onProgress, reject );

		} );

	}
A async version of {@link Loader#load}.

@param {string} url - The path/URL of the file to be loaded.
@param {onProgressCallback} [onProgress] - Executed while the loading is in progress.
@return {Promise} A Promise that resolves when the asset has been loaded.