Discuss Thread Safety concerning Singleton Dependencies.

Because a Singleton dependency is shared across all concurrent requests/threads, its internal state must be strictly thread-safe.

If a Singleton maintains state (like a dictionary cache or a counter), multiple threads accessing it simultaneously will cause race conditions, corrupt data, or throw concurrency exceptions. You must use thread-safe collections (e.g., ConcurrentDictionary) or synchronization primitives (lock, Mutex).