Identifies raw unknown-field bytes preserved during protobuf decoding.
Generated decoders store the original bytes on this symbol when they find
unknown fields. Generated encoders write the bytes again. This supports
forward compatibility when an older SDK reads a message with newer fields.
Identifies raw unknown-field bytes preserved during protobuf decoding.
Generated decoders store the original bytes on this symbol when they find unknown fields. Generated encoders write the bytes again. This supports forward compatibility when an older SDK reads a message with newer fields.