Status: IN
Both chat (inbox routing) and news feed (post ID distribution) push lightweight references at write time, deferring full data hydration to the read path — this shared pattern helps decouple write-time fanout cost from payload size in these two systems.
Reference-based fanout limits write amplification to pointer-sized payloads
Depends on (SL): chat-fanout-on-write, news-feed-fan-out-write-pushes-ids