skipStreamPayload function
Steps over a stream whose header has been read, without decoding it.
How a private or unrecognized attribute is passed by: the registry reserves ids 64–127 for applications and requires readers to skip them, and skipping means not decompressing — a private stream in a codec this build lacks must not fail a file that is otherwise perfectly readable.
Implementation
void skipStreamPayload(FourdgsCursor cursor, FourdgsStreamHeader header) =>
cursor.skip(header.payloadLength);