@Override
  public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
    process(roundEnv);
    return false;
  }
Issue a compilation error and return an exception that, when thrown, will cause the processing
of this class to be abandoned. This does not prevent the processing of other classes.
value/src/main/java/com/google/auto/value/processor/AutoAnnotationProcessor.java