Struct Lock 

pub struct Lock<'a> { /* private fields */ }

A sophisticated lock implementation designed for concurrent cuckoo filter operations.

This is NOT a traditional mutex but an atomic-based synchronization mechanism that enables three distinct concurrency modes:

1. Optimistic locks: Allow maximum concurrency - multiple readers and writers can proceed simultaneously. Used for optimistic reads that detect data races.

2. WriterExclusive locks: Mutual exclusion among writers only - prevents concurrent modifications but allows concurrent reads.

3. FullyExclusive locks: Complete mutual exclusion - blocks all operations. Only used during complex eviction chains to ensure consistency.

Version Encoding Scheme

The atomic usize encodes both lock state and version information:

• Bits 0-1: Lock kind (0=Optimistic, 1=WriterExclusive, 2=FullyExclusive)
• Bits 2-63: Version counter (incremented on FullyExclusive release)

This allows optimistic readers to detect when their read might be stale by comparing version numbers before and after the operation.

Trait Implementations

impl Drop for Lock<'_>

fn drop(&mut self)

Release the lock when it goes out of scope