perlio:  1 wallclock secs ( 1.04 usr +  0.07 sys =  1.11 CPU) @ 62.16/s (n=69)
   regular:  1 wallclock secs ( 0.92 usr +  0.20 sys =  1.12 CPU) @ 194.64/s (n=218)

##</code><code>##

     use PerlIO::via::MD5;
     use Digest::MD5 qw(md5_hex);
     use Benchmark qw(:all);
 
     my $file = "somebigfile.dat";
 
     timethese(-1, {
         perlio  => \&perlio,
         regular => \&regular,
     });
 
     sub perlio {
         open(my $in,"<:via(MD5)", $file)
             or die "Can't open file for digesting: $!\n";
         my $digest = <$in>;
         close $in;
         return $digest;
     }
 
     sub regular {
         local($/) = undef;
         open FILE, $file
             or die "Can't open file for digesting: $!\n";
         my $data = <FILE>;
         close FILE;
 
         return md5_hex($data);
     }