C#高性能Span類型

using System.ComponentModel;
using System.Reflection;
using System.Runtime.CompilerServices;

namespace System
{
    [DefaultMember("Item")]
    [IsByRefLike]
    [IsReadOnly]
    public struct Span<T>
    {
        public Span(T[] array);
        [CLSCompliant(false)]
        public Span(void* pointer, int length);
        public Span(T[] array, int start, int length);

        public ref T this[int index] { get; }

        public static Span<T> Empty { get; }
        public int Length { get; }
        public bool IsEmpty { get; }

        public void Clear();
        public void CopyTo(Span<T> destination);
        [EditorBrowsable(EditorBrowsableState.Never)]
        [Obsolete("Equals() on Span will always throw an exception. Use == instead.")]
        public override bool Equals(object obj);
        public void Fill(T value);
        public Enumerator GetEnumerator();
        [EditorBrowsable(EditorBrowsableState.Never)]
        [Obsolete("GetHashCode() on Span will always throw an exception.")]
        public override int GetHashCode();
        [EditorBrowsable(EditorBrowsableState.Never)]
        public ref T GetPinnableReference();
        public Span<T> Slice(int start);
        public Span<T> Slice(int start, int length);
        public T[] ToArray();
        public override string ToString();
        public bool TryCopyTo(Span<T> destination);

        public static bool operator ==(Span<T> left, Span<T> right);
        public static bool operator !=(Span<T> left, Span<T> right);

        public static implicit operator ReadOnlySpan<T>(Span<T> span);
        public static implicit operator Span<T>(ArraySegment<T> segment);
        public static implicit operator Span<T>(T[] array);

        [IsByRefLike]
        public struct Enumerator
        {
            public ref T Current { get; }

            public bool MoveNext();
        }
    }
}

Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
Span<StructDog> list = new Span<StructDog>();
for (long i = 0; i < 100000; i++)
{
	StructDog tank = new StructDog();
	tank.myProperty = i;
	tank.szSrcMach = "測試字符串" + i;
	tank.address = "武松打虎";
	tank.createTime = DateTime.Now;
	tank.phone = "18454648646";
	tank.updateTime = DateTime.Now;
	tank.weight = 58.623;
	tank.weight2 = 61.623;
	tank.weight3 = 61.623;
	tank.weight4 = 61.623;
	tank.childrenList1 = new List<StructDog2>() {
		 new StructDog2(){
			 color="紅色呢",weight=18585L
		 },
		  new StructDog2(){
			 color="棕色呢",weight=845858L
		 }
	 };
	tank.childrenList2 = new List<StructDog2>() {
		 new StructDog2(){
			 color="紅色呢",weight=18585L
		 },
		  new StructDog2(){
			 color="棕色呢",weight=845858L
		 }
	 };
	list.Fill(tank);
}
foreach (var item in list)
{
	long km = item.myProperty;
	string kmg = item.szSrcMach;
	string color = item.childrenList1[0].color;
	//Console.WriteLine("Hello World!" + item.myProperty);
}
stopwatch.Stop();
Console.WriteLine("耗時" + stopwatch.ElapsedMilliseconds);
Console.ReadKey();


public struct StructDog
    {
        public long myProperty;
        public string szSrcMach;
        public double weight;
        public double weight2;
        public double weight3;
        public double weight4;
        public DateTime createTime;
        public DateTime updateTime;
        public string name;
        public string phone;
        public string address;
        public List<StructDog2> childrenList1;
        public List<StructDog2> childrenList2; 
    }
    public struct StructDog2
    {
        public long weight;
        public string color;
    }

相同代碼用List實現，StructDog是class，不是結構struct ，會耗時多近一半時間，測試結果：
結論，Span高性能