import unittest adds 0.250s to script launch time

This should not be imported at root level, since it adds a lot of initialization overhead without need.

Author: wonder-mice

Diff for: git/util.py

@@ -20,7 +20,6 @@
 import stat
 from sys import maxsize
 import time
-from unittest import SkipTest
 from urllib.parse import urlsplit, urlunsplit
 import warnings
 
@@ -130,6 +129,7 @@ def onerror(func: Callable, path: PathLike, exc_info: str) -> None:
             func(path)  # Will scream if still not possible to delete.
         except Exception as ex:
             if HIDE_WINDOWS_KNOWN_ERRORS:
+                from unittest import SkipTest
                 raise SkipTest("FIXME: fails with: PermissionError\n  {}".format(ex)) from ex
             raise