use overload '""' => \&as_string, '0+' => \&as_number;

sub as_string {
    # Foo::Bar=HASH(0xDEADBEEF),tid=42

    my $self = shift @_;
    return overload::StrVal( $self ) . ',tid=' . $self->tid;
}

sub as_number {
    return shift->tid;
}