**arrayvec** provides the types `ArrayVec` and `ArrayString`:
array-backed vector and string types, which store their contents inline.
The **arrayvec** crate has the following cargo feature flags:
- `std`
- Optional, enabled by default
- Requires Rust 1.6 *to disable*
- Use libstd
- `use_union`
- Optional
- Requires Rust nightly channel
- Use the unstable feature untagged unions for the internal implementation,
which has reduced space overhead
- `use_generic_array`
- Optional
- Requires Rust stable channel
- Depend on generic-array and allow using it just like a fixed
size array for ArrayVec storage.