package My::File::Class;

use base 'IO::File';

use Class::InsideOut qw/public id register/;

public some_property => my %some_property;

sub new {
  my $class = shift;
  my $self = IO::File->new( @_ );
  register( bless $self, $class );
  return $self;
}

1;

##</code><code>##

use My::File::Class;

my $obj = My::File::Class->new( "filename.txt" );

$obj->some_property("foo");