print "Content-type: text/plain\n\n";

my $headers = {
    'headers'       => {
        'Authorization' => 'Bearer ' . $Site::Variables::stripe_secret,
    },
    'agent'         => 'Wayfinder/v3.0',
};

my $sub_id = 'sub_xxxxxx';

print Dumper $headers;
print "\n\n--------------\n\n";

# This line is the culprit...
my $res = $http->post_form("https://api.stripe.com/v1/subscriptions/$sub_id", {}, $headers);

print Dumper $headers;
print "\n\n--------------\n\n";