GuzzleHttp\Test\Handler\ProxyTest::testSendsToSync PHP Method

    public function testSendsToSync()
    {
        $a = $b = null;
        $m1 = new MockHandler([function ($v) use(&$a) {
            $a = $v;
        }]);
        $m2 = new MockHandler([function ($v) use(&$b) {
            $b = $v;
        }]);
        $h = Proxy::wrapSync($m1, $m2);
        $h(new Request('GET', 'http://foo.com'), [RequestOptions::SYNCHRONOUS => true]);
        $this->assertNull($a);
        $this->assertNotNull($b);
    }