Function stream_export_model_with_index 

pub fn stream_export_model_with_index(
    content: &[u8],
    entity_index: &Arc<EntityIndex>,
    f: impl FnMut(EntityRow),
) -> UnitScales

Like stream_export_model but reuses a pre-built entity index. A caller also running the geometry pass (crate::try_export_glb_with_stats_with_index) over the same bytes builds the index once with [build_entity_index] and shares it across both, skipping the duplicate scan. entity_index MUST be built from the same content; output is identical to stream_export_model. Returns the model’s UnitScales, so a caller consuming attribute values can interpret them without a second pass over the file: the scales are resolved from the decoder this function already builds.