Author: Asim Liaquat (asimlqt22@gmail.com)
Inheritance: implements Google\Spreadsheet\ServiceRequestInterface
 public function testInitRequest()
 {
     $method = new \ReflectionMethod(DefaultServiceRequest::class, "initRequest");
     $method->setAccessible(true);
     $request = new DefaultServiceRequest("token");
     $request->addHeader("k", "v");
     $result = $method->invoke($request, "http://test");
     $this->assertTrue(is_resource($result));
     $result = $method->invoke($request, "spreadsheet");
     $this->assertTrue(is_resource($result));
 }
 /**
  * {@inheritdoc}
  */
 protected function initRequest($url, $requestHeaders = [])
 {
     $this->accessToken = $this->refreshExpiredToken();
     return parent::initRequest($url, $requestHeaders);
 }