docs: private static Map<Method, OperationId> findMethods(Class<?> type) {
      Map<Method, OperationId> operations = new HashMap<>();
      for (Method method : type.getDeclaredMethods()) {
        OperationId operationId = getOperationId(method);
        if (operationId != null) {
          if (operations.values().stream().anyMatch(operation -> operation.id().equals(operationId.id()))) {
            throw new IllegalStateException("Duplicate operation name '" + operationId.id() + "'");
          }
          operations.put(method, operationId);
        }
      }
      for (Class<?> iface : type.getInterfaces()) {
        operations.putAll(findMethods(iface));
      }
      return operations;
    }