var t = Tuple.Create(123, DateTime.Now);

 public struct MyStruct
        {
            public int I { get; set; }
        }
        public class MyClass
        {
            public int I { get; set; } 
        }
  static void Main(string[] args)
        {
            var l = new List<MyStruct>() {new MyStruct() {I = 1}};
            var a = new[] {new MyStruct() {I = 1}};
            var l1 = new List<MyClass>() {new MyClass() {I = 1}};
            l1[0].I = 7;
            l[0].I = 2;
            a[0].I = 2;
}

class Program
{
  public struct MyStruct
  {
    public int I { get; set; }
  }
  static readonly MyStruct[] myStructs = new [] {new MyStruct{I=1} };
  static MyStruct GetMyStruct()
  {
    return myStructs[0];
  }
  static void Main(string[] args)
  {
    GetMyStruct().I = 2;
    Console.WriteLine("done");
    Console.ReadKey(true);
  }
}