title: Get consumer lag programmatically with broker based offsets
body: <p>I have been combing through the internet, literally, for a whole day and couldnt fine one working example.</p>
  
  <p>All I want is the consumer group lag metric (Or the 2 offsets its derived from, current and last), for a given groupID.</p>
  
  <p>Im using kafka 0.9+ (So no offsets in zookeeper) and can also use newer ones if needed.</p>
  
  <p>I need a way to get it <strong>programmatically, not using the scripts.</strong></p>
  
  <p>Someone, please, how do I get it?????</p>