anchor.diff:      {{ok,
         [{<<"status">>, <<"206">>},
          {<<"content-type">>, <<"multipart/byteranges">>},
  -       {<<"etag">>, ETag},
  -       {<<"cache-control">>, <<"public,max-age=1">>},
  -       {<<"expires">>, _},
  +       {<<"cache-control">>, <<"public">>},
  +       {<<"expires">>, _},
  +       {<<"etag">>, ETag},
          {<<"last-modified">>, LastModified},
          {<<"date">>, _},
          {<<"accept-ranges">>, <<"bytes">>}],
  
positive.code:       [{<<"status">>, <<"206">>},
         {<<"content-type">>,<<"application/octet-stream">>},
         {<<"content-range">>, <<"bytes 123-126/127">>},
         {<<"etag">>, ETag},
         {<<"cache-control">>, <<"public,max-age=1">>},
         {<<"expires">>, _},
         {<<"last-modified">>, LastModified},
         {<<"date">>, _},
         {<<"accept-ranges">>, <<"bytes">>}],
  
negative.code:     Request = <<>>,
      Timeout = undefined, % default
      Priority = undefined, % default
      {{ok,
        [{<<"content-type">>, <<"application/octet-stream">>},
         {<<"content-disposition">>,
          <<"attachment; filename=\"ASCII.bin\"">>},
         {<<"cache-control">>, <<"public">>},
         {<<"expires">>, _},
         {<<"etag">>, ETag},
         {<<"last-modified">>, LastModified},
         {<<"date">>, _},
         {<<"accept-ranges">>, <<"bytes">>}],
  