Major Description
Since KuduContext carries a bunch of information for client connection, such as authentication token, KuduContext should be created in the driver and shared with executors.
Even if we have put comments for KuduContext class (https://github.com/apache/kudu/blob/master/java/kudu-spark/src/main/scala/org/apache/kudu/spark/kudu/KuduContext.scala#L43), it would be great to provide a way to warn users (e.g Logging) about such behavior since this kind of issues are very subtle to detect.