request:
{
    "method": "subscribe",
    "module": "gameevents",
    "events": [
        "player_connect",
        "player_disconnect",
        "player_say",
        "invalid"
    ]
}

response:
{
    "method": "subscribe",
    "module": "gameevents",
    "error": 0,
    "events": [
        0,
        1,
        2,
        -3
    ]
}

-----

events:
{
    "method": "publish",
    "module": "gameevents",
    "event": {
        "name": "player_connect",
        "data": {
            "name": "BotoX",
            "index": 0,
            "userid": 4,
            "networkid": "[U:1:51174697]",
            "address": "192.168.1.4:27006",
            "bot": 0
        }
    }
}

{
    "method": "publish",
    "module": "gameevents",
    "event": {
        "name": "player_say",
        "data": {
            "text": "hello",
            "userid": 4
        }
    }
}

{
    "method": "publish",
    "module": "gameevents",
    "event": {
        "name": "player_disconnect",
        "data": {
            "userid": 4,
            "reason": "Disconnect by user.",
            "name": "BotoX",
            "networkid": "[U:1:51174697]",
            "bot": 0
        }
    }
}

-----

request:
{
    "method": "unsubscribe",
    "module": "gameevents",
    "events": [
        "player_connect",
        "player_disconnect",
        "player_say",
        "invalid"
    ]
}

response:
{
    "method": "unsubscribe",
    "module": "gameevents",
    "error": 0,
    "events": [
        0,
        0,
        0,
        0
    ]
}

-----

request:
{
    "method": "function",
    "function": "KickClient",
    "parameters": [
        1,
        "%d hello %s",
        1337,
        "cat"
    ]
}

Other examples:

{ "method": "function", "function": "PrintToServer", "parameters": ["1: %s, 2: %d, 3: %s, 4: %d", "1test1", [2222], "3test3", [4444]] }

{ "method": "function", "function": "TeleportEntity", "parameters": [1, [206.472443, 2418.516357, -62.058395], [26.994024, -14.119852, 0.000000], [["NULL_VECTOR"]] ] }

{ "method": "function", "function": "GetClientName", "parameters": [ 1, "", 1024 ] }

{ "method": "function", "function": "GetClientAbsOrigin", "parameters": [ 1, [0.0,0,0] ] }

{ "method": "function", "function": "ServerCommandEx", "parameters": [ "", 1024, "echo hello mates %d %f %s", [123], [123.456], "test" ] }

{ "method": "subscribe", "module": "gameevents", "events": [ "player_say" ] }

{ "method": "function", "function": "GetUserFlagBits", "args": [ 9 ] }