writable._destroy(err, callback)

• err <Error> 可能的错误。
• callback <Function> 一个可选接收错误参数的回调函数。

_destroy() 方法由 writable.destroy() 调用。
子类可以重写它，但绝对不能直接调用。

【The _destroy() method is called by writable.destroy(). It can be overridden by child classes but it must not be called directly.】