Protobuf\MessageCollection::offsetSet PHP Метод

    public function offsetSet($offset, $value)
    {
        if (!$value instanceof Message) {
            throw new InvalidArgumentException(sprintf('Argument 2 passed to %s must implement interface \\Protobuf\\Message, %s given', __METHOD__, is_object($value) ? get_class($value) : gettype($value)));
        }
        parent::offsetSet($offset, $value);
    }