stack_dst 0.4.3

A wrapper that allows storage of unsized values of up to a fixed size on the stack (requires nighly currently, to drop unsized types)
Documentation
Stack-allocated dynamically-sized types

# Overview
This crate provides a simple way of returnings DSTs up to a certain size without requiring a heap allocation.

# Basic usage
This crate provides two types - `Value` (which is a fixed-size allocation for a single DST), and `Stack` (a fixed-size buffer
for multiple DSTs arranged in a LIFO stack.

# Example
One of the most obvious uses is to allow returning capturing closures without having to box them. In the example below, the closure
takes ownership of `value`, and is saved to a StackDST
```rust
use stack_dst::Value as StackDST;

fn make_closure(value: u64) -> StackDST<Fn()->String> {
    StackDST::new(move || format!("Hello there! value={}", value)).ok().expect("Closure doesn't fit")
}
let closure = make_closure(12);
assert_eq!( closure(), "Hello there! value=12" );
```

# Status
- Works for most test cases
- Not rigourously tested

## 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.