Curl::request_multiple( array $requests, array $options )

	public function request_multiple($requests, $options) {
		// If you're not requesting, we can't get any responses ¯\_(ツ)_/¯
		if (empty($requests)) {
			return [];
		}

		if (InputValidator::has_array_access($requests) === false || InputValidator::is_iterable($requests) === false) {
			throw InvalidArgument::create(1, '$requests', 'array|ArrayAccess&Traversable', gettype($requests));
		}

		if (is_array($options) === false) {
			throw InvalidArgument::create(2, '$options', 'array', gettype($options));
		}

		$multihandle = curl_multi_init();
		$subrequests = [];
		$subhandles  = [];

		$class = get_class($this);
		foreach ($requests as $id => $request) {
			$subrequests[$id] = new $class();
			$subhandles[$id]  = $subrequests[$id]->get_subrequest_handle($request['url'], $request['headers'], $request['data'], $request['options']);
			$request['options']['hooks']->dispatch('curl.before_multi_add', [&$subhandles[$id]]);
			curl_multi_add_handle($multihandle, $subhandles[$id]);
		}

		$completed       = 0;
		$responses       = [];
		$subrequestcount = count($subrequests);

		$request['options']['hooks']->dispatch('curl.before_multi_exec', [&$multihandle]);

		do {
			$active = 0;

			do {
				$status = curl_multi_exec($multihandle, $active);
			} while ($status === CURLM_CALL_MULTI_PERFORM);

			$to_process = [];

			// Read the information as needed
			while ($done = curl_multi_info_read($multihandle)) {
				$key = array_search($done['handle'], $subhandles, true);
				if (!isset($to_process[$key])) {
					$to_process[$key] = $done;
				}
			}

			// Parse the finished requests before we start getting the new ones
			foreach ($to_process as $key => $done) {
				$options = $requests[$key]['options'];
				if ($done['result'] !== CURLE_OK) {
					//get error string for handle.
					$reason          = curl_error($done['handle']);
					$exception       = new CurlException(
						$reason,
						CurlException::EASY,
						$done['handle'],
						$done['result']
					);
					$responses[$key] = $exception;
					$options['hooks']->dispatch('transport.internal.parse_error', [&$responses[$key], $requests[$key]]);
				} else {
					$responses[$key] = $subrequests[$key]->process_response($subrequests[$key]->response_data, $options);

					$options['hooks']->dispatch('transport.internal.parse_response', [&$responses[$key], $requests[$key]]);
				}

				curl_multi_remove_handle($multihandle, $done['handle']);
				curl_close($done['handle']);

				if (!is_string($responses[$key])) {
					$options['hooks']->dispatch('multiple.request.complete', [&$responses[$key], $key]);
				}

				$completed++;
			}
		} while ($active || $completed < $subrequestcount);

		$request['options']['hooks']->dispatch('curl.after_multi_exec', [&$multihandle]);

		curl_multi_close($multihandle);

		return $responses;
	}