blocking 0.4.3

Block on async code or await blocking code
Documentation
# Version 0.4.3

- Fix a bug where a closed `Receiver` causes panics.

# Version 0.4.2

- Start thread numbering from 1.

# Version 0.4.1

- Attach names to spawned threads.

# Version 0.4.0

- Remove `Future` impl for `Blocking`.
- Add `unblock()`.
- Rename `blocking!` to `unblock!`.
- Rename `Blocking` to `Unblock`.
- Add `block_on()`, `block_on!`, and `BlockOn`.

# Version 0.3.2

- Make `Blocking` implement `Send` in more cases.

# Version 0.3.1

- Add `Blocking::with_mut()`.

# Version 0.3.0

- Remove `Blocking::spawn()`.
- Implement `Future` for `Blocking` only when the inner type is a `FnOnce`.

# Version 0.2.0

- Initial version

# Version 0.1.0

- Reserved crate name