pub fn initials<'a>(
        &'a self,
    ) -> impl Iterator<Item = PackageMetadata<'g>> + ExactSizeIterator + 'a {
        let graph = self.graph;
        self.params.initials().iter().map(move |package_ix| {
            graph
                .metadata(&graph.dep_graph[*package_ix])
                .expect("valid ID")
        })
    }
Returns the list of initial packages specified in the query.

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