GetPing 

Namespace: SynicSugar.P2P
Class: p2pInfo

public int GetPing(UserId id)

Description 

Get the ping with a peer from cache.
The ping with a disconnected user is -1.

using UnityEngine;
using UnityEngine.UI;
using SynicSugar.P2P;

public class p2pSample : MonoBehaviour {
    public Text ping;
    public void DisplayPing(){
        ping.text = $"{OwnerUserId}: {p2pInfo.Instance.GetPing(OwnerUserId)}";
    }
}