docs: @Override
      public long getLastKnownTick()
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
          {
              SibTr.entry(this, tc, "getLastKnownTick");
              SibTr.exit(tc, "getLastKnownTick", Long.valueOf(unknownHorizon));
          }
  
          return unknownHorizon;
      }