void resume();
activity::ActivityImplPtr join(ActorImpl* actor, double timeout);
activity::ActivityImplPtr sleep(double duration);
/** Ask the actor to throw an exception right away */
void throw_exception(std::exception_ptr e);
void resume();
activity::ActivityImplPtr join(ActorImpl* actor, double timeout);
activity::ActivityImplPtr sleep(double duration);
/** Ask the actor to throw an exception right away */
void throw_exception(std::exception_ptr e);