CustomNetworkManager.OnStartServer C# (CSharp) Method

    public override void OnStartServer()
    {
        // The server registers the function 'customAddPlayer' and associates it with an ID.
        // When the server hears the particular ID, the function is called.
        // When the function is called, a class of type MessageBase is sent to the server in addition to other info
        // Such as the connection ID and so on.
        NetworkServer.RegisterHandler(9001, customAddPlayer);
        NetworkServer.RegisterHandler(9002, forceSceneReload);
    }