private static void checkMapString(String name, Class<?> type, Type genericType) {
      checkState(Map.class.isAssignableFrom(type), "%s parameter must be a Map: %s", name, type);
      checkMapKeys(name, genericType);
    }
Called indirectly by {@link #parseAndValidateMetadata(Class)}.
core/src/main/java/feign/Contract.java