@Override
  public boolean hasUnregistered() {
    // Nothing to do. No registration involved.
    return true;
  }
The difference between this and getTotalResources() is that this only gives currently free
resource instances, while the other lists all the instances that may become available in a
while.
llap-tez/src/java/org/apache/hadoop/hive/llap/tezplugins/LlapTaskSchedulerService.java