using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Threading.Tasks;
public string Firstname { get; }
public string Lastname { get; }
public Sample(string firstname, string lastname)
public static bool operator ==(Sample obj1, Sample obj2) => false;
public static bool operator !=(Sample obj1, Sample obj2) => true;
static async Task Main(string[] args)
if (test is null) Console.WriteLine("YES it is NULL (test is null)");
if (test == null) Console.WriteLine("YES it is NULL (test == null)");