OptionalauthorOptionaldataOptionalidOverride the file id.
OptionalifcxOverride the IFCX version string. Defaults to whatever was seeded.
OptionalslotEmit only the entities of one model slot (#4444), paths kept as stored (slot-qualified), with THAT slot's file header / imports / schemas. A recipient reconstructs one viewer model per slot from one snapshot per slot. Omitted: every entity in the room, file metadata merged across slots (see slot-ifcx.ts).
OptionalsortStable child-key ordering (defaults to insertion order from the Y.Map).
OptionaltimestampOverride timestamp; defaults to Date.now().
Override the data version string.