Module cache 

Caching layer for VelesDB (SOTA 2026).

Based on arXiv:2310.11703v2 recommendations:

• LRU cache for metadata-only collections
• Bloom filter for existence checks
• Cache statistics and monitoring

Thread-Safety & Lock Ordering

All structures are thread-safe via parking_lot::RwLock.

Lock Hierarchy (acquire in this order to prevent deadlocks):

1. BloomFilter.bits (RwLock)
2. BloomFilter.count (RwLock)
3. LruCache.inner (RwLock)

Structs

BloomFilter

Bloom filter for probabilistic existence checks.

CacheStats

Cache statistics for monitoring.

LockFreeCacheStats

Statistics for the two-tier cache.

LockFreeLruCache

Lock-free two-tier cache with DashMap L1 and LruCache L2.

LruCache

Thread-safe LRU cache with O(1) operations.