PUBLISHPost a message to a channel; returns the receiver count.
| Syntax | PUBLISH channel message |
| Group | pubsub |
| Arity | 3 |
| Since | 1.0.0 |
| Flags | readonly, pubsub |
| Complexity | O(1) channel lookup + O(P) — a linear walk of the registered patterns with one glob match each, even when none match. Delivery fans out only to the shards holding a subscriber |
| Redis compatibility | full |