QNetworkRequest is already aware of the Last-Modified header but
has been lacking support for the If-Modified-Since, ETag, If-Match
and If-None-Match headers. These headers are used with HTTP to
signal conditional download requests.
See RFC 7232 for more information.
Change-Id: I248577b28e875fafd3e4c44fb31e8d712b6c14f1
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
b0726e8641