ImmutableListMultimap<ExecutableElement, AnnotationMirror> propertyMethodAnnotationMap(
      TypeElement type, ImmutableSet<ExecutableElement> propertyMethods) {
    ImmutableListMultimap.Builder<ExecutableElement, AnnotationMirror> builder =
        ImmutableListMultimap.builder();
    for (ExecutableElement propertyMethod : propertyMethods) {
      builder.putAll(propertyMethod, propertyMethodAnnotations(type, propertyMethod));
    }
    return builder.build();
  }
Returns the fully-qualified name of an annotation-mirror, e.g.
"com.google.auto.value.AutoValue".
value/src/main/java/com/google/auto/value/processor/AutoValueishProcessor.java