Module-wide multi overriding

multi-overrides.pm6

use v6;

unit module Foo;

our proto sub bar(|) {*}
multi bar(
    Hash $config,
    *%sig where { is-overridden $config, $?PACKAGE, &?ROUTINE }) {
    override($config<overrides>{ me }, :$config, :%sig);
}

# default core version of bar
multi bar() {
  return "blah";
}

# %config looks like this
# %{
#       overrides => %{ 'Foo::bar' => 'MyOtherModule::bar' }
# }