"Write-rarely-read-many" wrapper.

This lock-free container is suitable in situations where you perform a lot of reads to a T, but only rarely modify that T.

From a logic point of view, it is more or less the equivalent of an RwLock, except that:

• It works in no_std platforms.
• Reading the T always takes the same time and will never wait for a lock to be released.
• Writing the T is done in a compare-and-swap way, and updates might have to be performed multiple times.

See the documentation of the [Wrrm].

Example

let val = wrrm::Wrrm::from(5);
assert_eq!(*val.access(), 5);

val.modify_with(|v| *v += 1);
assert_eq!(*val.access(), 6);