exit-future 0.1.0

Future that signals exit to many receivers
Documentation
## [Documentation](https://docs.rs/exit-future)
----

Create a `Signal` and cloneable `Exit` future that fires when `Signal` is fired or dropped. Used to coordinate exit between multiple event-loop threads.

```rust
let (signal, exit) = exit_future::signal();

::std::thread::spawn(move || {
    // future resolves when signal fires
    exit.wait().unwrap();
});

signal.fire(); // also would fire on drop.
```