Explain the atomic orderings used in race

src/race.rs

@@ -5,6 +5,18 @@
 //! them stores the result.
 //!
 //! This module does not require `std` feature.
+//!
+//! # Atomic orderings
+//!
+//! All types in this module use `Acquire` and `Release`
+//! [atomic orderings](Ordering) for all their operations. While this is not
+//! strictly necessary, it is useful for users as it allows them to be certain
+//! that after `get` or `get_or_init` returns on one thread, any side-effects
+//! caused by the setter thread prior to them calling `set` or `get_or_init`
+//! will be made visible to that thread; without it, it's possible for it to
+//! appear as if they haven't happened yet from the getter thread's perspective.
+//! This is an acceptable tradeoff to make since `Acquire` and `Release` have
+//! very little performance overhead on most architectures versus `Relaxed`.
 
 #[cfg(feature = "atomic-polyfill")]
 use atomic_polyfill as atomic;