The simplest event emitter for rust
```rust fn main () { use aloneee::eventemitter::EventEmitter; let ee = EventEmitte::Stringr::new();
let subscription = ee.on(Box::new(|ev| { // listener will be alive till subscription is alive
// do something
println!("hello {}", ev.data());
Ok(())
}));
ee.once(Box::new(|ev| { // listener will be alive till subscription is alive or next emit will fired
// do something
println!("hello {} one more time", ev.data());
Ok(())
}));
ee.emit("world");
// you will see
// "hello world"
// "hello world one more time"
drop(subscription); // unbind the listener
} ```