system/HTTP/DownloadResponse.php
public function setFilePath(string $filepath)
	{
		if ($this->binary !== null)
		{
			throw DownloadException::forCannotSetFilePath($filepath);
		}

		$this->file = new File($filepath, true);
	}
public function setFilePath(string $filepath)
	{
		if ($this->binary !== null)
		{
			throw DownloadException::forCannotSetFilePath($filepath);
		}

		$this->file = new File($filepath, true);
	}
set download for file.

@param string $filepath