box.broadcast()
- 
 
box.broadcast(key, value)¶ Update the value of a particular key and notify all key watchers of the update.
Параметры: - key (
string) – key name of the event to subscribe to - value – any data that can be encoded in MsgPack
 
Return: none
Possible errors:
- The value can’t be encoded as MsgPack.
 - The key refers to a 
box.system event 
Example:
-- Broadcast value 42 for the 'foo' key. box.broadcast('foo', 42)
- key (