tent-type');
        $contentType = explode(';', $contentType);
        $boundary = false;
        foreach ($contentType as $part) {
            $part = explode('=', $part, 2);
            if (isset($part[0]) && 'boundary' == trim($part[0])) {
                $boundary = $part[1];
            }
        }

        $body = (string) $response->getBody();
        if (!empty($body)) {
            $body = str_replace("--$boundary--", "--$boundary", $body);
            $parts = explode("--$boundary", $body);
            $responses = [];
            $requests = array_values($this->requests);

            foreach ($parts as $i => $part) {
                $part = trim($part);
                if (!empty($part)) {
                    list($rawHeaders, $part) = explode("\r\n\r\n", $part, 2);
                    $headers = $this->parseRawHeaders($rawHeaders);

                    $status = substr($part, 0, strpos($part, "\n"));
                    $status = explode(" ", $status);
                    $status = $status[1];

                    list($partHeaders, $partBody) = $this->parseHttpResponse($part, 0);
                    $response = new Response(
                        (int) $status,
                        $partHeaders,
                        Psr7\Utils::streamFor($partBody)
                    );

                    // Need content id.
                    $key = $headers['content-id'];

                    try {
                        $response = REST::decodeHttpResponse($response, $requests[$i-1]);
                    } catch (GoogleServiceException $e) {
                        // Store the exception as the response, so successful responses
                        // can be processed.
                        $response = $e;
                    }

                    $responses[$key] = $response;
                }
            }

            return $responses;
        }

        return null;
    }

    private function parseRawHeaders($rawHeaders)
    {
        $headers = [];
        $responseHeaderLines = explode("\r\n", $rawHeaders);
        foreach ($responseHeaderLines as $headerLine) {
            if ($headerLine && strpos($headerLine, ':') !== false) {
                list($header, $value) = explode(': ', $headerLine, 2);
                $header = strtolower($header);
                if (isset($headers[$header])) {
                    $headers[$header] = array_merge((array)$headers[$header], (array)$value);
                } else {
                    $headers[$header] = $value;
                }
            }
        }
        return $headers;
    }

    /**
     * Used by the IO lib and also the batch processing.
     *
     * @param string $respData
     * @param int $headerSize
     * @return array
     */
    private function parseHttpResponse($respData, $headerSize)
    {
        // check proxy header
        foreach (self::$CONNECTION_ESTABLISHED_HEADERS as $established_header) {
            if (stripos($respData, $established_header) !== false) {
                // existed, remove it
                $respData = str_ireplace($established_header, '', $respData);
                // Subtract the proxy header size unless the cURL bug prior to 7.30.0
                // is present which prevented the proxy header size from being taken into
                // account.
                // @TODO look into this
                // if (!$this->needsQuirk()) {
                //   $headerSize -= strlen($established_header);
                // }
                break;
            }
        }

        if ($headerSize) {
            $responseBody = substr($respData, $headerSize);
            $responseHeaders = substr($respData, 0, $headerSize);
        } else {
            $responseSegments = explode("\r\n\r\n", $respData, 2);
            $responseHeaders = $responseSegments[0];
            $responseBody = isset($responseSegments[1]) ? $responseSegments[1] : null;
        }

        $responseHeaders = $this->parseRawHeaders($responseHeaders);

        return [$responseHeaders, $responseBody];
    }
}