public User(string name, string account, int age, List <string> roles, DateTime birthday, ClassModel classInfo)
 {
     //模拟耗时操作
     CoreService.CostTime(5);
     this.Name      = name;
     this.Account   = new StringBuilder(account);
     this.Age       = age;
     this.Roles     = roles;
     this.Birthday  = birthday;
     this.ClassInfo = classInfo;
     Console.WriteLine("User被构造了");
 }
 public User()
 {
     //模拟耗时操作
     CoreService.CostTime(5);
     Console.WriteLine("User被无参构造了");
 }