pub fn initials<'a>(
        &'a self,
    ) -> impl Iterator<Item = FeatureMetadata<'g>> + ExactSizeIterator + 'a {
        let graph = self.graph;
        self.params
            .initials()
            .iter()
            .map(move |feature_ix| graph.metadata_for_ix(*feature_ix))
    }
Returns the list of initial features specified in the query.

The order of features is unspecified.
guppy/src/graph/feature/query.rs