my %hash = (
   'w',
   x => $x,
   y => $y,
   z => $z,
);

##</code><code>##

my %hash = (
   w => w(),  # Returns <1 or >1 elements
   x => $x,
   y => $y,
   z => $z,
);

##</code><code>##

(
    size => 374205,                 \ or vice-versa
    type => "image/jpeg",           /

    "charset=utf-8; Content-Transfer-Encoding: binary",  XXX

    headers => $headers,
    tempname => "/tmp/5xSW7Swasp",
    filename => "aaa.jpg",
)