title: set offsetRange() function in pyspark rdd kafka
body: <p>I successfully integrated kafka and spark.
  I want send streaming from kafka to spark.and now I am able to send stream to spark.I want this stream in RDD so I used createRDD() function to create rdds.
  But I got only some masseges from kafka in rdd. because it depend on offset range.So please anyone can tell me how to set offsetRange() in kafka-spark CreateRDD() function.</p>