string-clone


        // Method required for the ICloneable interface.IClonable接口所需的方法。
        // There's no point in cloning a string since they're immutable, so we simply return this.
// 克隆字符串没有意义,因为它们是不可变的,所以我们只返回这个。
public Object Clone() { Contract.Ensures(Contract.Result() != null); Contract.EndContractBlock(); return this; }