public function getLastModified()
	{
		$mtime = 0;
		
		foreach($this->instrumentors as $instrumentor)
		{
			$mtime = max($mtime, filemtime((new \ReflectionClass($instrumentor))->getFileName()));
			
			if($instrumentor instanceof CachingInstrumentorInterface)
			{
				$mtime = max($mtime, $instrumentor->getLastModified());
			}
		}
		
		return (int)$mtime;
	}