Set method errors on NX condition mismatch

[Luzifer]

From the Redis documentation:

Simple string reply: OK if SET was executed correctly. Null reply: a Null Bulk Reply is returned if the SET operation was not performed because the user specified the NX or XX option but the condition was not met.
https://redis.io/commands/set

Within the code the Set method performs an OKValue check which expects to see a StatusReply only. Therefore setting NX to true causes the error invalid reply type, not status even though the command was executed successfully and should not cause an error.