@Override
    public synchronized void init(ProcessingEnvironment processingEnv) {
      super.init(processingEnv);
      elements = processingEnv.getElementUtils();
      types = processingEnv.getTypeUtils();
    }
Flag to track if test statement was executed or not. Fail fast if annotation processor
was not triggered. IE detected false (no-op) test executions
processor-testlib/src/org/immutables/value/processor/meta/ProcessorRule.java