pub fn parse_paging_header<R: Read>(
first: u64,
r: &mut R,
) -> Result<(PagingKind, u64, u64)>Expand description
Parse the paging handshake header after the caller has read the first u64.
v2-only: the first u64 MUST be PAGING_MAGIC_V2, then
[u8 kind][u64 arena_bytes][u64 blob_bytes]. blob_bytes == 0 = the RAW
one-sided mode (per-connection arena, client-owned allocator — the caller
routes it OFF the paging registry). Rejects unsupported kinds (≥2), the
retired v1 magic (dedicated diagnostic so a stale binary fails legibly),
and any other first u64 (e.g. a bare legacy total_bytes).