static void LibeventSendCallback(int fd, short event, void *arg);
static void LibeventReceiveCallback(int fd, short event, void *arg);
static void RecvDatagram (evutil_socket_t socket); // Called by LibeventReceiveCallback
static void LibeventSendCallback(int fd, short event, void *arg);
static void LibeventReceiveCallback(int fd, short event, void *arg);
static void RecvDatagram (evutil_socket_t socket); // Called by LibeventReceiveCallback