code: function HistoricalScheduler(initialClock, comparer) {
        var clock = initialClock == null ? 0 : initialClock;
        var cmp = comparer || defaultSubComparer;
        __super__.call(this, clock, cmp);
      }
docs: Creates a new historical scheduler with the specified initial clock value.
  @constructor
  @param {Number} initialClock Initial value for the clock.
  @param {Function} comparer Comparer to determine causality of events based on absolute time.