Re: Last-Modified header in 304 and 206 responses

> In RFC2616, Last-Modified header was not allowed in 304 and 206(to an
> If-Range request)
>
>  http://tools.ietf.org/html/rfc2616#section-10.3.5
>  http://tools.ietf.org/html/rfc2616#section-10.2.7
>
> In draft 19, Last-Modified is allowed/required in 206/If-Range, but
> still forbidden in 304
>
>  http://tools.ietf.org/html/draft-ietf-httpbis-p4-conditional-19#section-4.1
>  http://tools.ietf.org/html/draft-ietf-httpbis-p5-range-19#section-3.1
>
> Any reason for the asymmetry?
>
> Furthermore, why must we exclude other entity headers in 304 and
> 206/If-Range? There are only 3 of them: Content-Encoding,
> Content-Language, Content-Type. They can't have any meaningful impact
> on performance if they are included in the response. Do they really
> deserve a "SHOULD NOT be included"?
>
> Zhong Yu
>