} else if (src_buff_ != nullptr) {
on_send(*this);
send(sender_, mailbox_, remains_, rate_, src_buff_, src_buff_size_, match_fun_, copy_data_function_,
} else if (src_buff_ != nullptr) {
on_send(*this);
send(sender_, mailbox_, remains_, rate_, src_buff_, src_buff_size_, match_fun_, copy_data_function_,