MSG_CHILD_STARTED
AWAIT_INT_MESSAGE(sock_fds[1], MSG_CHILD_STARTED);
SEND_INT_MESSAGE(sock_fds[0], MSG_CHILD_STARTED);
SEND_INT_MESSAGE(pipefds[1], MSG_CHILD_STARTED);
AWAIT_INT_MESSAGE(pipefds[0], MSG_CHILD_STARTED);
SEND_INT_MESSAGE(sock_fds[0], MSG_CHILD_STARTED);
AWAIT_INT_MESSAGE(sock_fds[1], MSG_CHILD_STARTED);
SEND_INT_MESSAGE(pipefds[1], MSG_CHILD_STARTED);
AWAIT_INT_MESSAGE(pipefds[0], MSG_CHILD_STARTED);
SEND_INT_MESSAGE((int)(intptr_t)arg, MSG_CHILD_STARTED);
AWAIT_INT_MESSAGE(thread_pipefds[1], MSG_CHILD_STARTED);
SEND_INT_MESSAGE(pipefds[1], MSG_CHILD_STARTED);
AWAIT_INT_MESSAGE(pipefds[0], MSG_CHILD_STARTED);
SEND_INT_MESSAGE(pipefds[1], MSG_CHILD_STARTED);
AWAIT_INT_MESSAGE(pipefds[0], MSG_CHILD_STARTED);
SEND_INT_MESSAGE(pipefds[1], MSG_CHILD_STARTED);
AWAIT_INT_MESSAGE(pipefds[0], MSG_CHILD_STARTED);
SEND_INT_MESSAGE(pipefds[1], MSG_CHILD_STARTED);
AWAIT_INT_MESSAGE(pipefds[0], MSG_CHILD_STARTED);
SEND_INT_MESSAGE(pipefds[1], MSG_CHILD_STARTED);
AWAIT_INT_MESSAGE(pipefds[0], MSG_CHILD_STARTED);