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use Sub::Prepend 'prepend';

...
__END__
Foo was called with @_ = (3).
Foo executed with @_ = (3).

my $old = \&foo;
*foo = sub { ...; goto &$old };

use Scalar::Util 'set_prototype';

...
  no warnings 'redefine';
  *$name = $new;
}

prepend(foo => sub { ... });

prepend(foo => sub ($) { ... });
prepend(foo => sub { ... }, { prototype => '$' });