解析Unirest PHP的响应

Question

我正在使用Unirest PHP调用API。它看起来像这样：

$response = Unirest\Request::post(
                    "url_to_api",
                         array(
                               "api" => "my_api_key",
                               "Content-Type" => "application/json"
                                )
json_encode(array("parameters" => [100, 200]))
                              );
print_r($response->body);

响应正文包含很多信息。这是一个stdClass对象。我怎么解析这个？我尝试像在JSON中那样解析它，但是我收到了一个错误。响应如下：

stdClass Object ( [requestId] => blahblah [status] => Succeeded [elapsedTimeInMs] => 0 [warnings] => Array ( [0] => elapsedTimeInMs is deprecated. Please use the timing headers instead. [1] => status is deprecated. Please use HTTP status codes to determine the status of a request. ) [release] => stdClass Object ( [version] => 13 [commitId] => 275342fakeid5737425 [file] => test.R [function] => add_nums ) [result] => Array ( [0] => 300 ) )

我想要的只是响应中的300，发生在最后。