Design a multi-threaded synchronous log writer

### Problem Design a log writer component that is called from **multiple application threads** and writes logs to a **single file on disk**. Requirements: - Callers can log concurrently: `log(message)` may be invoked by many threads. - Writes must be **synchronous/durable**: once `log()` returns, the message must be persisted such that it survives a process crash (assume you must `fsync`/flush). - Preserve a well-defined ordering (e.g., FIFO based on call time, or per-thread order—state your choice). - High throughput: avoid doing an `fsync` per message if possible. ### Tasks - Propose an implementation approach (data structures, threading model). - Explain how you ensure durability, ordering, and performance. - Discuss failure modes (disk full, partial writes, crash during write) and how to handle them.