code: Map getPassThruProps() {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(this, tc, "getPassThruProps");
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(this, tc, "getPassThruProps", passThruProps);
          return passThruProps;
      }
docs: Return the passThruProps for this Session.