Concurrency Coding: Implement Thread-Safe Components Using Locks and Atomics

Implement several thread-safe concurrency primitives/components (classic concurrency coding questions). Requirements: The code must be correct under multi-threaded access with no race conditions. You must be proficient with locks (mutex/RWLock/condition variables) and their correct usage. You must be proficient with atomics (CAS) and avoid conflicts, deadlocks, and other concurrency bugs. Note: The original post does not list the exact components to implement (e.g., thread-safe queue, LRU, RWLock, barrier, rate limiter, etc.), so this is a high-level category and needs specific sub-questions to be actionable.