REPL.TOKEN
kevy extension: mint a read-your-writes token — per-shard [generation, offset] pairs (a primary reports its live feed tail; a replica its applied positions).
REPL.TOKENComplexity
O(S) — one (generation, offset) pair per shard
Complexity and compatibility are read out of kevy's implementation, not copied from Redis's reference. Several genuinely differ.
Redis compatibility
kevy only
kevy has this; Redis does not. the read-your-writes token; the nearest Redis concept is master_repl_offset, which is not a resumable per-shard cursor