Status: IN
_NO_DEFAULT is a sentinel object distinguishing "no default provided" from a None/null default; this matters because null is a valid Avro default value, and conflating the two would break canonical form computation and default-filling during resolution.
Source: entries/2026/05/29/avro-serializer-avro_serializer.md
_NO_DEFAULT = object()
# distinguishes "no default" from "default is None"