message: make constantSource accessible from within the class
diff: @@ -35,7 +35,7 @@ implements AbstractParam<Type> {
  /**
  * The constant source node which generates the signal
  */
  - private _constantSource: ConstantSourceNode = this.context.createConstantSource();
  + protected _constantSource: ConstantSourceNode = this.context.createConstantSource();
  readonly output: OutputNode = this._constantSource;
  protected _param: Param<Type>;
  readonly input: InputNode;
  