private static Object fieldValue(Field field, Object container) {
    try {
      return field.get(container);
    } catch (IllegalAccessException e) {
      throw new RuntimeException(e);
    }
  }
Returns the result of substituting the variables defined by the fields of this class (a
concrete subclass of TemplateVars) into the template returned by {@link #parsedTemplate()}.
value/src/main/java/com/google/auto/value/processor/TemplateVars.java