open $fh, "<", $^X or die;
binmode $fh;
print "1: ", join(' ', PerlIO::get_layers($fh, details => 1)), "\n";
close $fh;

open $fh, "<:raw:perlio", $^X or die;
print "2: ", join(' ', PerlIO::get_layers($fh, details => 1)), "\n";
close $fh;