不透明响应
An opaque filtered response is a filtered response whose type is "opaque", url list is the empty list, status is 0, status message is the empty byte sequence, header list is empty, body is null, and trailer is empty.
An opaque-redirect filtered response is a filtered response whose type is "opaqueredirect", status is 0, status message is the empty byte sequence, header list is empty, body is null, and trailer is empty.