public function setBody($body): :endpoint
    {
        if (isset($body) !== true) {
            return $this;
        }
        if (is_array($body) === true || $body instanceof Traversable) {
            foreach ($body as $item) {
                $this->body .= $this->serializer->serialize($item) . "\n";
            }
        } elseif (is_string($body)) {
            $this->body = $body;
            if (substr($body, -1) != "\n") {
                $this->body .= "\n";
            }
        } else {
            throw new InvalidArgumentException("Body must be an array, traversable object or string");
        }
        return $this;
    }