It's possible to do without init_arg (which I didn't know about for the longest time either), but it's less clear.

for my $field (qw( server peer monitor netlog )) {
   my $object = "${field}_object";
   has $field => (
      reader   => $object,
      isa      => 'NetAddr::IP',
      coerce   => 1,
      required => 1,
      handles  => {
         $field => sub { $_[0]->$object->addr },
      },
   );
}
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