toml_edit presents Table as a mapping between Key and Value with KeyMut for providing access to the subset of key functionality that the user can modify. Internally, this is stored as IndexMap<String, (Key, Value)>, where Key contains a String, among other data.

Key.get().clone() to get the String key is showing up in my benchmarks in parsing a real-world Cargo.toml file. I'm exploring my options for avoiding that

I hadn't noticed MutableKeys before and it seems like a good start by allowing me to instead do IndexMap<Key, Value>. Some parts I'm missing for maintaining my KeyMut access for users:

• MutableKeys::iter_full_mut2
• MutableOccupiedEntrykeys::get_full_mut2

There may be more as I've not fully gone through my compilation errors. I'm more wondering if this direction is viable before I continue down this path.

I'd be willing to contribute these if there is interest.