public ActorMessageDispatcher(IAgency agency)
 {
     Agency = agency;
     Agent  = Agency.GetAgentFor <TActor>();
 }
 public SagaMessageDispatcher(IAgency agency, Saga.ISaga <TActor> saga)
 {
     Agency = agency;
     Agent  = Agency.GetAgentFor <TActor>();
     Saga   = saga;
 }