Fixed #9084 - Best approach for an OS to atomically rename the session file.

import datetime

import errno

import os

import shutil

import tempfile

from django.conf import settings

                    os.write(output_file_fd, self.encode(session_data).encode())

                finally:

                    os.close(output_file_fd)

                os.rename(output_file_name, session_file_name)

                # This will atomically rename the file (os.rename) if the OS

                # supports it. Otherwise this will result in a shutil.copy2

                # and os.unlink (for example on Windows). See #9084.

                shutil.move(output_file_name, session_file_name)

                renamed = True

            finally:

                if not renamed: