pub fn resolve_with_fn(
        self,
        resolver_fn: impl FnMut(&PackageQuery<'g>, PackageLink<'g>) -> bool,
    ) -> PackageSet<'g> {
        self.resolve_with(ResolverFn(resolver_fn))
    }
Resolves this query into a set of known packages, using the provided resolver function
to determine which links are followed.
guppy/src/graph/query.rs