Unknown LEN fields in protobuf-es carry raw wire bytes including the
length varint (BinaryReader.skip captures it; BinaryWriter.raw replays
verbatim after the tag). The fallback for unnamed permission-query
variants wrote 'approved {}' as bare 0a 00, producing a frame the
server cannot decode (the 0a is read as a length of 16). Prefix the
payload with its length and lock the wire shape with a round-trip test.
can1357
0ac4e01b7b