How to calculate ping between server and client?

I have a socket server in nodejs, a unity client and I try calculate the latency between them like below Server:

socket.on("readable", () => {
    let data: Buffer = socket.read();
    if(data !== null) {
        let length: number = parseInt(bufferStream.subarray(0, maxDataLength).toString("hex"), 16);
        let dataBuffer : Buffer = bufferStream.subarray(maxDataLength, maxDataLength + length);
        let data: string = dataBuffer.toString('utf-8');
        let json: any = JSON.parse(data);
        switch (json._event.event_name) {
            case 'ping':
                let pingData = {
                    event_name : "pong"
                }
                socket.write((PrepareData(pingData));
                break;
        }
    }
});

Client:

class PingData
{
    public static float start = 0;
    public static bool pinged = false;
}

private async void SocketReading()
{
    if (socket.Available == 0)
    {
        return;
    }
    byte[] buf = new byte[socket.Available];
    await socket.ReceiveAsync(buf, SocketFlags.None);
    buffer.AddRange(buf);
}

private void ProcessBuffer()
{
    byte[] lengthField = buffer.Take(4).ToArray();
    int dataLength = BitConverter.ToInt32(lengthField, 0);

    byte[] dataField = buffer.Skip(4).Take(dataLength).ToArray();
    string response = Encoding.UTF8.GetString(dataField);

     EventName _event = JsonUtility.FromJson<EventName>(response);

    switch (_event.event_name)
    {
        case "pong":
        Debug.Log((Time.time - PingData.start) * 1000f);
        PingData.pinged = false;
        break;
        //other cases
    }
}

public void Ping()
{
    SendData<PingEvent> data = new SendData<PingEvent>(new PingEvent());
    Send(JsonUtility.ToJson(data));
    PingData.start = Time.time;
    PingData.pinged  = true;
}

Is this the correct way to get the ping between server and client? Because the log give very high number (20-100) even when test in same computer.