SyncRequest

{
    "since": 0,
    "client_id": "string",
    "active_cid": "string",
    "message_cursors": {
        "property1": 0,
        "property2": 0
    },
    "message_change_cursors": {
        "property1": [],
        "property2": []
    },
    "message_delete_cursors": {
        "property1": [],
        "property2": []
    }
}