return (

on(atom("pong"), arg_match) >> [num_pings](int value) {

CPPA_LOGF_ERROR_IF(!self->last_sender(), "last_sender() == nullptr");

CPPA_LOGF_INFO("received {'pong', " << value << "}");

//cout << to_string(self->last_dequeued()) << endl;

if (++s_pongs >= num_pings) {

CPPA_LOGF_INFO("reached maximum, send {'EXIT', user_defined} "

<< "to last sender and quit with normal reason");

send_exit(self->last_sender(), exit_reason::user_defined);

self->quit();

}

else reply(atom("ping"), value);

},

others() >> [] {

CPPA_LOGF_ERROR("unexpected message; "

<< to_string(self->last_dequeued()));

self->quit(exit_reason::user_defined);

}

);

return (

on(atom("ping"), arg_match) >> [](int value) {

CPPA_LOGF_INFO("received {'ping', " << value << "}");

reply(atom("pong"), value + 1);

},

others() >> [] {

CPPA_LOGF_ERROR("unexpected message; "

<< to_string(self->last_dequeued()));

self->quit(exit_reason::user_defined);

}

);

CPPA_SET_DEBUG_NAME("ping");

CPPA_LOGF_TRACE("num_pings = " << num_pings);

s_pongs = 0;

receive_loop(ping_behavior(num_pings));

CPPA_SET_DEBUG_NAME("event_based_ping");

CPPA_LOGF_TRACE("num_pings = " << num_pings);

s_pongs = 0;

become(ping_behavior(num_pings));

CPPA_SET_DEBUG_NAME("pong");

CPPA_LOGF_TRACE("ping_actor = " << to_string(ping_actor));

send(ping_actor, atom("pong"), 0); // kickoff

receive_loop(pong_behavior());

CPPA_SET_DEBUG_NAME("event_based_pong");

CPPA_LOGF_TRACE("ping_actor = " << to_string(ping_actor));

CPPA_REQUIRE(ping_actor != nullptr);

send(ping_actor, atom("pong"), 0); // kickoff

become(pong_behavior());