pub fn prop010_id_strategy(&self) -> impl Strategy<Value = FeatureId<'g>> + 'g {
        let dep_graph = self.dep_graph();
        let package_graph = self.package_graph;
        any::<prop::sample::Index>().prop_map(move |index| {
            let feature_ix = NodeIndex::new(index.index(dep_graph.node_count()));
            FeatureId::from_node(package_graph, &dep_graph[feature_ix])
        })
    }
Returns a `Strategy` that generates random feature IDs from this graph.

The IDs so chosen are uniformly random from the entire feature graph. In other words, a
package with more optional features is more likely to be chosen.

Requires the `proptest1` feature to be enabled.

## Panics

Panics if there are no packages in the `PackageGraph` from which this `FeatureGraph` was
derived.
guppy/src/graph/feature/proptest_helpers.rs