Returns the operating system's default directory for temporary files as a

string.

On Windows, the result can be overridden by `TEMP` and `TMP` environment variables, and

`TEMP` takes precedence over `TMP`. If neither is set, it defaults to `%SystemRoot%\temp`

or `%windir%\temp`.

On non-Windows platforms, `TMPDIR`, `TMP` and `TEMP` environment variables will be checked

to override the result of this method, in the described order. If none of them is set, it

defaults to `/tmp`.

Some operating system distributions would either configure `TMPDIR` (non-Windows) or

`TEMP` and `TMP` (Windows) by default without additional configurations by the system

administrators. The result of `os.tmpdir()` typically reflects the system preference

unless it's explicitly overridden by the users.