AgoraVideoViewController.swift

import AgoraRtcKit

let appID = "YourAppIDHere"
var agoraKit: AgoraRtcEngineKit?
let tempToken: String? = nil //If you have a token, put it here.
var userID: UInt = 0 //This tells Agora to generate an id for you. If you have unique user IDs already, you can use those.

...

private func getAgoraEngine() -> AgoraRtcEngineKit {
    if agoraKit == nil {
        agoraKit = AgoraRtcEngineKit.sharedEngine(withAppId: appID, delegate: self)
    }
    return agoraKit!
}