ExitSession 

Namespace: SynicSugar.P2P
Class: ConnectHub

public async UniTask<bool> ExitSession(bool destroyManager = true, bool cleanupMemberCountChanged = false, CancellationToken cancelToken = default(CancellationToken))

Description 

Stop the packet receiver, close all connections, remove the notify events and destroy ConnectManager object. Then, the user leaves Lobby.
The last user closes the lobby in Backend.

destroyManager: If true, destroy NetworkManager after exit lobby.
cleanupMemberCountChanged: Need to call MatchMakeManager.Instance.MatchMakingGUIEvents.LobbyMemberCountChanged(id, false) after exit lobby?
cancelToken: ancel token for this task

using SynicSugar.P2P;
using System.Threading;

public class p2pSample {
    public async void ConnectHubSample(){
        await ConnectHub.Instance.ExitSession();
    }
}