I'm using Azure RedisCache, and when I call the following command:
_cache.KeyDelete(key, CommandFlags.HighPriority)
The key is not deleted and there are no errors.
Similarly, nor does the following work if a key/value is already set:
_cache.StringSet(dataKey, "")
_cache.KeyExpire(dataKey, DateTime.UtcNow.AddDays(-2), CommandFlags.HighPriority)