private function writeCache($data)
	{
		$this->cacheMap[$this->hash] = time();
		$handle = fopen($this->cacheMapFile, "w");
		flock($handle, LOCK_EX);
		$write1 = fwrite($handle, 
			json_encode(
				$this->cacheMap, 
				JSON_UNESCAPED_SLASHES
			)
		);
		fclose($handle);
		$handle = fopen($this->cacheFile, "w");
		flock($handle, LOCK_EX);
		$write2 = fwrite($handle, $data);
		fclose($handle);
		return (
			(bool) $write1 && (bool) $write2
		);
	}