 is in progress. An AsyncSlice consumes no CPU time
   * itself and so is only associated with Threads at its start and end point.
   *
   * @constructor
   */
  function AsyncSlice(category, title, colorId, start, args, duration,
      opt_isTopLevel, opt_cpuStart, opt_cpuDuration,
      opt_argsStripped) {
    tr.model.TimedEvent.call(this, start);

    this.category = category || '';
    // We keep the original title from the trace file in originalTitle since
    // some sub-classes, e.g. NetAsyncSlice, 