#!/usr/bin/perl
use strict;
use warnings;
use Fcntl qw(:DEFAULT);
use Data::Dumper;
require Data::Dumper;
local $Data::Dumper::Purity;
$Data::Dumper::Purity = 1;
local $Data::Dumper::Useqq;
$Data::Dumper::Useqq = 1;
local $Data::Dumper::Sortkeys;
$Data::Dumper::Sortkeys = sub {
    my ($hash) = @_;
    return [(sort {lc $a cmp lc $b} keys %$hash)];
};
use 5.010;

require IO::String;
require MIME::Explode;
my $fhin = IO::String->new("Date: Sat, 16 Apr 2016 17:24:09 +0200\nSubject: Testsubject\n\nTesttext");
my $fhout = IO::String->new();
my $explode = MIME::Explode->new(
    decode_subject      => 1,
    check_content_type  => 1,
    types_action        => 'include',
);
if (my $headers = $explode->parse(*$fhin,*$fhout)) {
    say Dumper($headers);
    say '#########################################';
    say "Out: '${$fhout->string_ref}'";
}