Hash-indexed collection
==============

You could call this a cache, or a kind of set. It is a simple wrapper around
`HashSet` to allow values of type `T` to be stored in a set indexed by some
type `K`, where values of type `K` can be somehow "extracted" from those of
type `T`.

Check documentation on type `HashIndexed` for usage.


## License

Licensed under either of

 * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)

at your option.

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any
additional terms or conditions.