manual_future

Explicitly completed Future type for Rust, similar to Java's CompletableFuture

Example

```rust // create a new, incomplete ManualFuture let (future, completer) = ManualFuture::new();

// complete the future with a value completer.complete(5).await;

// retrieve the value from the future assert_eq!(future.await, 5);

// you can also create ManualFuture instances that are already completed asserteq!(ManualFuture::newcompleted(10).await, 10); ```