Since we support multiple versions of Rust, there are often features which
have been stabilized in the most recent stable release which do not yet
exist (stably) on our MSRV. This module provides polyfills for those
features so that we can write more “modern” code, and just remove the
polyfill once our MSRV supports the corresponding feature. Without this,
we’d have to write worse/more verbose code and leave TODO comments sprinkled
throughout the codebase to update to the new pattern once it’s stabilized.