src/Message/AbstractRestRequest.php
public function toJSON($data, $options = 0)
    {
        // Because of PHP Version 5.3, we cannot use JSON_UNESCAPED_SLASHES option
        // Instead we would use the str_replace command for now.
        // TODO: Replace this code with return json_encode($this->toArray(), $options | 64); once we support PHP >= 5.4
        if (version_compare(phpversion(), '5.4.0', '>=') === true) {
            return json_encode($data, $options | 64);
        }
        return str_replace('\\/', '/', json_encode($data, $options));
    }
public function toJSON($data, $options = 0)
    {
        // Because of PHP Version 5.3, we cannot use JSON_UNESCAPED_SLASHES option
        // Instead we would use the str_replace command for now.
        // TODO: Replace this code with return json_encode($this->toArray(), $options | 64); once we support PHP >= 5.4
        if (version_compare(phpversion(), '5.4.0', '>=') === true) {
            return json_encode($data, $options | 64);
        }
        return str_replace('\\/', '/', json_encode($data, $options));
    }
Returns object JSON representation required by PayPal.
The PayPal REST API requires the use of JSON_UNESCAPED_SLASHES.

Adapted from the official PayPal REST API PHP SDK.
(https://github.com/paypal/PayPal-PHP-SDK/blob/master/lib/PayPal/Common/PayPalModel.php)

@param int $options http://php.net/manual/en/json.constants.php
@return string