Execute external program (nslookup) in c# asynchronously to resolve domain MX records.

Program.cs

using System;
using System.Diagnostics;
using System.Threading.Tasks;

namespace DNSResolve
{
    class Program
    {
        public static async Task Main(string[] args)
        {
            var lookupResponse = await RunProcessAsync("google.com");
            Console.WriteLine(lookupResponse);
        }

        private static async Task<string> RunProcessAsync(string domain)
        {
            var tcs = new TaskCompletionSource<string>();

            var proc = new Process
            {
                StartInfo = new ProcessStartInfo
                {
                    FileName = "nslookup",
                    Arguments = $"-q=mx {domain}",
                    UseShellExecute = false,
                    RedirectStandardOutput = true,
                    CreateNoWindow = true
                },
                EnableRaisingEvents = true
            };

            proc.Exited += (sender, args) =>
            {
                tcs.SetResult(proc.StandardOutput.ReadToEnd());
                proc.Dispose();
            };

            proc.Start();

            return await tcs.Task;
        }
    }
}