此函数现在跨平台一致，并且不再返回任何平台上带有斜杠的路径。
新增于: v0.9.9
以字符串形式返回操作系统默认的临时文件的目录。
This function is now cross-platform consistent and no longer returns a path with a trailing slash on any platform.
Added in: v0.9.9
Returns the operating system's default directory for temporary files as a string.