This is a handler for sending and receiving Game Coordinator messages. Initialize it by passing a SteamClient instance and an AppID to the constructor.

var steamGameCoordinator = new Steam.SteamGameCoordinator(steamClient, 570);

It's intended to have the same API as SteamClient's 'message'/send except it uses a different CMsgProtoBufHeader.

Sending and receiving Game Coordinator messages is designed to be symmetrical, so the event and the method are documented together. Both have the following arguments:

• header - an object representing the message header. It has the following properties:
  • msg - the game-specific "type" of the message (no protomask).
  • proto - a CMsgProtoBufHeader object if this message is protobuf-backed, otherwise header.proto is falsy. The fields job_id_source and job_id_target are reserved for internal use and shall be ignored. (Note: pass an empty object if you don't need to set any fields)
• body - a Buffer containing the rest of the message. (Note: in SteamKit2's terms, this is "Body" plus "Payload")
• callback (optional) - if not falsy, then this message is a request, and callback shall be called with any response to it instead of 'message'/send. callback has the same arguments as 'message'/send.

The 'message' event is only emitted by a SteamGameCoordinator instance if it was initialized with the same AppID as that of the incoming message. When sending a message, it uses the AppID it was initialized with.