OptionalexExpire the key after this many seconds (EX).
OptionalexatExpire the key at this UNIX time in seconds (EXAT).
OptionalkeepRetain the key's existing TTL (KEEPTTL).
OptionalnxOnly set the key if it does not already exist (NX).
OptionalpxExpire the key after this many milliseconds (PX).
OptionalpxatExpire the key at this UNIX time in milliseconds (PXAT).
OptionalxxOnly set the key if it already exists (XX).
Options for RedisSession.set.