Status: IN
`_write_hint_file` and `_load_hint_file` must use identical binary layouts: `[HINT_FORMAT header (24 bytes)][key_len uint32 (4 bytes)][key_bytes (variable)]` per entry; any change to one without the other breaks backward compatibility.
Source: entries/2026/05/28/hash-index-storage-bitcask-_write_hint_file.md