static void Main(string[] args)
  {
      ConcurrentDictionary<int, string> dict = new ConcurrentDictionary<int, string>();
      dict.TryAdd(1, "January");   //returns true
      dict.TryAdd(2, "February");  //returns true
      dict.TryAdd(3, "March");     //returns true
      dict.TryAdd(4, "April");     //returns true

      string removedItem;
      bool result = dict.TryRemove(4, out removedItem); //Returns true
      Console.WriteLine(removedItem); //Returns "April"
  }