src/Request/GET.php
public function setBody($body)
    {
        if (is_array($body) || is_object($body)) {
            $body = http_build_query($body);
        }
        $this->body = $body;
        return $this;
    }
public function setBody($body)
    {
        if (is_array($body) || is_object($body)) {
            $body = http_build_query($body);
        }
        $this->body = $body;
        return $this;
    }
@inheritdoc

Convert Body to Query String