presto-redis/src/main/java/io/prestosql/plugin/redis/RedisHandleResolver.java/RedisHandleResolver/convertSplit
class RedisHandleResolver:    static RedisSplit convertSplit(ConnectorSplit split)
    {
        requireNonNull(split, "split is null");
        checkArgument(split instanceof RedisSplit, "split is not an instance of RedisSplit");
        return (RedisSplit) split;
    }