code: protected <T extends InvocationMarshaller<?>> T addDispatcher (InvocationDispatcher<T> disp)
      {
          T marsh = _invmgr.registerDispatcher(disp);
          _marshallers.add(marsh);
          return marsh;
      }
docs: Registers an invocation dispatcher and notes the registration such that it will be
  automatically cleared when this manager shuts down.