message: don't warn on sync'ed start
diff: @@ -208,9 +208,9 @@ export abstract class Source<Options extends SourceOptions> extends ToneAudioNod
  this._syncedStart(this.now(), this.context.transport.seconds);
  }
  } else {
  + assertContextRunning(this.context);
  this._start(computedTime, offset, duration);
  }
  - assertContextRunning(this.context);
  }
  return this;
  }
  