Starts a usermessage (network message).
Handle StartMessage(const char msgname, const int clients, int numClients, int flags)
Message name to start.
Array containing player indexes to broadcast to.
Number of players in the array.
Optional flags to set.
A handle to a bf_write bit packing structure, or INVALID_HANDLE on failure.
Invalid message name, unable to start a message, invalid client, or client not connected.
Only one message can be active at a time.
It is illegal to send any message while a non-intercept hook is in progress.