pub fn exploded_schema(oid_len: usize) -> SchemaRefExpand description
Schema v2 (2026-09-04): enc sits BEFORE payload, so the payload’s data
buffer stays the LAST buffer of the batch — which is what
[payload_data_offset] reads the extent off. A v1 file has no enc column;
every reader treats a missing column as ENC_RAW, so pools written before
this open unchanged and are never rewritten for it.