pub fn encode_journal_schema() -> Result<Vec<u8>>Expand description
Serialize the journal’s schema message — the header an Arrow IPC stream opens with, emitted once per segment.
Both durable arms call it, and each writes it once per journal file:
SafeWriter when it finds the file empty,
UringWriter at offset 0 of the one it
creates. One encoder, one format, two transports (LAW 5) — and a
second schema message inside one file is what would make read_journal()
stop early, which is why neither arm can emit it per writer.