What is the status of incremental xDS support?
The incremental xDS protocol is designed to improve efficiency, scalability and functional use of xDS updates via two mechanisms:
Delta xDS. Resource deltas are delivered rather than state-of-the-world.
On-demand xDS. Resource can be lazy loaded depending on request contents.
Currently, all xDS protocols (including ADS) support delta xDS. On-demand xDS is supported for VHDS only.