Imgix API Image Purge with Guzzle 5

imgix.php

<?php
use Guzzle\Http\Client;
use Guzzle\Http\Exception\ClientErrorResponseException;

private function purgeImgixCache($imageUrl)
{
    $client = new Client();

    try {
        $request = $client->post('https://api.imgix.com/v2/image/purger',
            [
                'Content-Type'  => 'application/json',
                'Authorization' => 'Basic ' . base64_encode('THIS_IS_API_KEY_STRING' . ':')
            ],
            [
                'url' => $imageUrl
            ]
        );

        $response = $request->send();
    } catch (ClientErrorResponseException $exception) {
        $responseBody = $exception->getResponse()->getBody(true);

        return false;
    }

    return $response;
}