Returns @array-reply of keys from a full Redis command.
COMMAND GETKEYS is a helper command to let you find the keys
from a full Redis command.
COMMAND shows some commands as having movablekeys meaning
the entire command must be parsed to discover storage or retrieval
keys. You can use COMMAND GETKEYS to discover key positions
directly from how Redis parses the commands.
@return
@array-reply: list of keys from your command.
@examples
COMMAND GETKEYS MSET a b c d e f
COMMAND GETKEYS EVAL "not consulted" 3 key1 key2 key3 arg1 arg2 arg3 argN
COMMAND GETKEYS SORT mylist ALPHA STORE outlist