private static ImmutableSet<ExecutableElement> memoizedMethods(Context context) {
    return methodsIn(context.autoValueClass().getEnclosedElements()).stream()
        .filter(m -> getAnnotationMirror(m, MEMOIZED_NAME).isPresent())
        .collect(toImmutableSet());
  }
An extension that implements the {@link com.google.auto.value.extension.memoized.Memoized}
contract.
value/src/main/java/com/google/auto/value/extension/memoized/processor/MemoizeExtension.java