private byte[] HandleMutate(string commandName, string[] commandParams)
{
var key = _helpers.ToKey(commandParams[0]);
var incr = ulong.Parse(commandParams[1]);
byte[] resultData;
bool result = _cache.Mutate(key, incr, out resultData, commandName == "incr");
return(result && resultData != null
? resultData.Concat(_endOfLine).ToArray()
: Encoding.ASCII.GetBytes("NOT_FOUND\r\n"));
}