net.stun: Fix parsing of STUN packets with 0-length attributes Not sure where the '20' came from. RFC 8489 defines attributes as simple TLVs, with the type+length header being always 16 bits (4 bytes). The branch for non-zero lengths already uses the correct header size.

-- Unknown platform stub
module:set_global();

-- TODO Do things that make sense if we don't know about the platform