unknownFieldsKey top-level constant

String const unknownFieldsKey

Reserved message-map key under which a decoded message stores the raw bytes (tag + value, in wire order) of fields not in its descriptor, so marshal can re-emit them. The $ prefix cannot collide with a real proto field name. Skipped by the descriptor-driven marshalers, appended verbatim by marshal.

Implementation

const String unknownFieldsKey = r'$unknown';