例如在PUT的时候，加入If-Modified-Since参数，返回501 Not Implemented错误
请求示例：
PUT /bucket/my-image.jpg HTTP/1.1 Host: storage.aliyun.com Date: Wed, 28 May 2011 22:32:00 GMT If-Modified-Since: Wed, 06 Apr 2011 10:02:46 GMT返回消息头示例:
501 Not Implemented x-oss-request-id: 77E534EBF90372BE Content-Type: application/xml Transfer-Encoding: chunked Date: Thu, 28 Apr 2011 08:03:07 GMT Connection: close Server: AliyunOSS返回消息体示例:
<?xml version="1.0" ?> <Error> <Code> NotImplemented </Code> <Message> A header you provided implies functionality that is not implemented. </Message> <Header> If-Modified-Since </Header> <RequestId> 77E534EBF90372BE </RequestId> <HostId> storage.aliyun.com </HostId> </Error>