title: How to cache observable in RxJava/RxScala
body: <p>I have a REST API that calling mongodb using the reactive scala driver which based on RxScala. </p>
  
  <p>In my API controllers or services layers, I need to use caching to avoid calls to mongodb using hazelcast (or any other caching tools)</p>
  
  <p>All my services are async and returns only observable, any idea how I can implement the caching with observable?</p>