ReadonlynameA short identifier, surfaced in diagnostics and the parity tests.
Zig-zag then varint-encode each element.
Encode each element as an unsigned varint.
Pack each element as a little-endian fp32 (4 bytes).
Pack each element as a little-endian fp64 (8 bytes).
Bulk, capacity-guaranteed transforms used on the encoder's fast path.
Every method writes into
outstarting atpos, assuming the caller has already ensured enough room, and returns the position just past the last byte written. Headers, counts, flushing and validation stay in the stream classes; a kernel only moves bytes.