pub fn to_package_set_registry<'g, 'a>(
        &'a self,
        graph: &'g PackageGraph,
        registry_name_to_url: impl FnMut(&str) -> Option<&'a str>,
        error_message: impl Into<String>,
    ) -> Result<PackageSet<'g>, Error> {
        let error_message = error_message.into();
        let (package_set, matcher) =
            self.to_package_set_impl(graph, registry_name_to_url, &error_message)?;
        matcher.finish(graph, error_message)?;
        Ok(package_set)
    }
Converts this `PackageSetSummary` to a [`PackageSet`], with the given source for registry
names.

Returns an error if any of the elements weren't matched.

This is a temporary workaround until [Cargo issue #9052](https://github.com/rust-lang/cargo/issues/9052)
is resolved.
guppy/src/graph/summaries/package_set.rs