must_future

BoxFutures cannot be marked #[must_use] because they are just type definitions. This newtype struct wraps a BoxFuture with something that can be marked #[must_use].

Will Not Compile:

```compile_fail

![deny(unusedmustuse)]

use futures::future::FutureExt;

[tokio::main]

async fn main() { fn getfuture() -> mustfuture::MustBoxFuture<'static, ()> { async { }.boxed().into() }

get_future(); // unused `must_future::MustBoxFuture` that must be used

} ```