| EndMessage | Ends a previously started user message (network message). |
| GetUserMessageId | Returns the ID of a given message, or -1 on failure. |
| GetUserMessageName | Retrieves the name of a message by ID. |
| GetUserMessageType | Returns usermessage serialization type used for the current engine |
| HookUserMessage | Hooks a user message. |
| StartMessage | Starts a usermessage (network message). |
| StartMessageAll | Starts a usermessage (network message) that broadcasts to all clients. |
| StartMessageEx | Starts a usermessage (network message). |
| StartMessageOne | Starts a simpler usermessage (network message) for one client. |
| UnhookUserMessage | Removes one usermessage hook. |
| UserMessageToBfRead | Make sure to only call this on readable buffers (eg from a message hook). |
| UserMessageToBfWrite | Make sure to only call this on writable buffers (eg from StartMessage). |
| UserMessageToProtobuf | |