public void trackFailure(){
  retryTime=Utils.currentTimeMillis() + (long)backoff;
  backoff=Math.min(backoff * params.multiplier,params.maximum);
}

public void trackFailure ( ) { retryTime = Utils . currentTimeMillis ( ) + ( long ) backoff ; backoff = Math . min ( backoff * params . multiplier , params . maximum ) ; }
track a failure - multiply the back off interval by the multiplier
