static void Main(string[] args)
{
    string url = "www.stackoverflow.com";
    var pingTask = PingUrlAsync(url);
    Console.WriteLine($"Waiting for response from {url}");
    Task.WaitAll(pingTask);            
    Console.WriteLine(pingTask.Result);
}

static async Task<string> PingUrlAsync(string url)
{
    string response = string.Empty;
    var ping = new System.Net.NetworkInformation.Ping();

    var result = await ping.SendPingAsync(url);

    await Task.Delay(5000); //simulate slow internet

    if (result.Status == System.Net.NetworkInformation.IPStatus.Success)
    {
        response = $"{url} is online";
    }

    return response;
}