Not entirely sure if this is expected behaviour, but it surprised me. When the SetAdd(Async) methods are used with an empty array of values, there is a broken call made to redis.

To reproduce:

var redisConnection = ConnectionMultiplexer.Connect("localhost");
redisConnection.GetDatabase().SetAdd("set1", new RedisValue[0]);

This also fails for SetAddAsync.

Version: 2.0.601
Tested with dotnetcore 2.2 and 3.0