#### or, make required accept undef and use a predicate test
-has 'foo' => ( isa => 'Int | Undef', is => 'rw', coerce => 1, lazy_build => 1 );
-has 'bar' => ( isa => 'Int | Undef', is => 'rw', coerce => 1 );
+has 'foo' => ( isa => 'Int | Undef', is => 'rw', lazy_build => 1 );
+has 'bar' => ( isa => 'Int | Undef', is => 'rw' );
sub _build_foo { undef }