PUBLISHPost a message to a channel; returns the receiver count.
| 语法 | PUBLISH channel message |
| 分组 | pubsub |
| 参数个数 | 3 |
| 起始版本 | 1.0.0 |
| 标志 | readonly, pubsub |
| 复杂度 | 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 兼容性 | full |