protected function handleHEAD(): ResponseInterface
	{

		// Extension Thunder TUS Express: create the file on HEAD request
		if ($this->extExpress) {
			$this->response = $this->handlePOST();
			$code           = $this->response->getStatusCode();
			if ($code !== 201 && $code !== 409)
				return $this->response;
			$this->response = $this->response->withHeader("Location", $this->location);
		}
		else { // For Standard TUS
			if (!is_file($this->file))
				return $this->response->withStatus(404);
		}

		// Standard TUS HEAD response
		$localSize = filesize($this->file);

		return $this->response->withStatus(200)
		                      ->withHeader("Upload-Offset", $localSize);

	}