Method on_sender_drain_start

cpp/src/handler.cpp:89–89

void messaging_handler::on_tracker_settle(tracker &) {}
void messaging_handler::on_delivery_settle(delivery &) {}
void messaging_handler::on_sender_drain_start(sender &) {}
void messaging_handler::on_receiver_drain_finish(receiver &) {}

void messaging_handler::on_error(const error_condition& c) { throw proton::error(c.what()); }