Never use crate:: inline in code. Always do an appropriate import.
Imports must always be clustered together so no duplicate use crate:: lines.
use parking_lot::Mutex as SyncMutex; is the canonical sync mutex.
use async_lock::Mutex as AsyncMutex; is the canonical async mutex.
Internal logic errors should never fail gracefully. Always use .unwrap() to
enforce explicit failure. Error handling is for the topmost layers coming from
the edge of the app such as user input.
