sendAsyncRequest example

$this->assertSame('application/json', $response->getHeaderLine('content-type'));

        $body = json_decode((string) $response->getBody(), true);

        $this->assertSame('HTTP/1.1', $body['SERVER_PROTOCOL']);
    }

    public function testSendAsyncRequest()
    {
        $client = new HttplugClient(new NativeHttpClient());

        $promise = $client->sendAsyncRequest($client->createRequest('GET', 'http://localhost:8057'));
        $successCallableCalled = false;
        $failureCallableCalled = false;
        $promise->then(function DResponseInterface $response) use (&$successCallableCalled) {
            $successCallableCalled = true;

            return $response;
        }, function D\Exception $exception) use (&$failureCallableCalled) {
            $failureCallableCalled = true;

            throw $exception;
        });