message: making constructor arg optional
diff: @@ -52,7 +52,8 @@ export class Meter extends ToneAudioNode<MeterOptions> {
  /**
  * @param smoothing The amount of smoothing applied between frames.
  */
  - constructor(smoothing: NormalRange);
  + constructor(smoothing?: NormalRange);
  + // tslint:disable-next-line: unified-signatures
  constructor(options?: Partial<MeterOptions>);
  constructor() {
  super(optionsFromArguments(Meter.getDefaults(), arguments, ["smoothing"]));
  