pub fn named_features(&self) -> impl Iterator<Item = &'g str> + 'g {
        self.named_features_full()
            .map(|(_, named_feature, _)| named_feature)
    }
Returns the list of named features available for this package. This will include a feature
named "default" if it is defined.

A named feature is listed in the `[features]` section of `Cargo.toml`. For more, see
[the reference](https://doc.rust-lang.org/cargo/reference/manifest.html#the-features-section).
guppy/src/graph/graph_impl.rs