message: implemented the TODO feature
  removing comment
diff: @@ -48,8 +48,6 @@ export class StateTimeline<AdditionalOptions extends {} = {}> extends Timeline<S
  * @param options Any additional options that are needed in the timeline.
  */
  setStateAtTime(state: PlaybackState, time: Seconds, options?: AdditionalOptions): this {
  - // all state changes need to be >= the previous state time
  - // TODO throw error if time < the previous event time
  this.add(Object.assign({}, options, {
  state,
  time,
  