Basho\Riak\Api\Http::prepareRequestData PHP Method

    protected function prepareRequestData()
    {
        // if POST or PUT, add parameters to post data, else add to uri
        if (in_array($this->command->getMethod(), ['POST', 'PUT'])) {
            $this->requestBody = $this->command->getEncodedData();
            $this->options[CURLOPT_POSTFIELDS] = $this->requestBody;
        }
        return $this;
    }