FEED.TAILReturn a shard's current feed generation and next offset.
| Syntax | FEED.TAIL shard |
| Group | feed |
| Arity | 2 |
| Since | 3.0.0 |
| Flags | readonly, extension |
| Complexity | O(1) on a single shard |
| Redis compatibility | kevy-only: nearest is INFO replication's master_repl_offset, which is not a resumable per-shard CDC cursor |