Here's one method. Doubtless there's a neater approach but this works for your single example. Feel free to add to @tests to convince yourself that it is doing what you want.

#!/usr/bin/env perl 
use strict;
use warnings;
use Encode;
use Test::More;

my @tests = (
    {
        source => "\x{2013}",
        want => 'E2 80 93'
    }
);

plan tests => scalar @tests;

for my $t (@tests) {
    Encode::_utf8_off ($t->{source});           # bytes
    my $have = uc unpack "H*", $t->{source};    # into hex
    $have = join (' ', $have =~ /(..)/g);       # spaced pairs
    is ($have, $t->{want}, "Covert $t->{source} into $t->{want}");
}
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