public class ProteType    {             private static ProteType _ProteType = new ProteType();        private ProteType() { }        public static ProteType GetInstance()        {            return (ProteType)_ProteType.MemberwiseClone();        }            }

var a1 = ProteType.GetInstance();                var a2 = ProteType.GetInstance();                Console.WriteLine($"a1 和 a2 是同一实例：{ object.ReferenceEquals(a1, a2)}");