How to validate backup and restore operations using Bun's file I/O APIs?

Bun provides an all‑in‑one toolkit with fast built‑in tools and file I/O APIs (e.g., Bun.file) that can be used to read, write, and verify data. When designing a backup and restore workflow, what steps should be taken to ensure the backup is correct and the restore reproduces the original state? Consider approaches such as checksum comparison, streaming validation, and atomic file replacement.