Itertools — extra iterator adaptors, functions and macros.
To use the iterator methods in this crate, import the [`Itertools` trait](./trait.Itertools.html):
```
use itertools::Itertools;
```
## Crate Features
- `use_std`
- Enabled by default.
- Disable to compile itertools using `#![no_std]`. This disables
any items that depend on collections (like `group_by`, `unique`,
`kmerge`, `join` and many more).
## Rust Version
This version of itertools requires Rust 1.12 or later.