use Benchmark qw(:all);
use Encode;

my $chr = pack "U", 0x20AC;

cmpthese(1000000, {
    'Encode' => sub{
        my $len = length encode_utf8($chr);
        my $bin = pack("N", $len).encode_utf8($chr);
    },
    'uBytes' => sub{
        use bytes;
        my $bin = pack("N", length $chr).$chr;
    },
});


            Rate Encode uBytes
Encode  204499/s     --   -87%
uBytes 1524390/s   645%     --