To get the participant list.

SocketHelper.swift

func participantList(completion: @escaping (_ userList: [User]?) -> Void) {
        
        guard let socket = manager?.defaultSocket else {
            return
        }
        
        socket.on(kUserList) { [weak self] (result, ack) -> Void in
            
            guard result.count > 0,
                let _ = self,
                let user = result.first as? [[String: Any]],
                let data = UIApplication.jsonData(from: user) else {
                    return
            }
            
            do {
                let userModel = try JSONDecoder().decode([User].self, from: data)
                completion(userModel)
                
            } catch let error {
                print("Something happen wrong here...\(error)")
                completion(nil)
            }
        }
        
    }