Importer crash in parallel import on windows.

[henry-oberholtzer]

I think the threaded implementation is doing something unsafe where it is moving a temp file and then grabbing an incorrect one.

Traceback (most recent call last):
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\util\__init__.py", line 508, in move
    os.replace(syspath(path), syspath(dest))
FileNotFoundError: [WinError 2] The system cannot find the file specified: '\\\\?\\E:\\Incoming\\Mindscape – Black Lotus (2007) {CITRUSCD002} [FLAC]\\CD  01 (Unmixed)\\01 Mindscape & Jade & Hydro - Black Lotus (Break Remix).flac' -> '\\\\?\\E:\\Media Library\\Music\\Digital\\m\\Mindscape\\Black Lotus (2007, Citrus Recordings CITRUSCD002) [FLAC 16-44]\\1-01 - Mindscape + Jade + Hydro - Black Lotus (Break Remix).1.flac'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "c:\users\henry\.local\bin\beet.exe\__main__.py", line 5, in <module>
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\ui\__init__.py", line 1645, in main
    _raw_main(args)
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\ui\__init__.py", line 1624, in _raw_main
    subcommand.func(lib, suboptions, subargs)
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\ui\commands\import_\__init__.py", line 131, in import_func
    import_files(lib, byte_paths, query)
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\ui\commands\import_\__init__.py", line 75, in import_files
    session.run()
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\importer\session.py", line 237, in run
    pl.run_parallel(QUEUE_SIZE)
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\util\pipeline.py", line 471, in run_parallel
    raise exc_info[1].with_traceback(exc_info[2])
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\util\pipeline.py", line 383, in run
    self.coro.send(msg)
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\util\pipeline.py", line 195, in coro
    task = func(*args, task)
           ^^^^^^^^^^^^^^^^^
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\importer\stages.py", line 299, in manipulate_files
    task.manipulate_files(
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\importer\tasks.py", line 483, in manipulate_files
    item.move(operation)
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\library\models.py", line 1164, in move
    self.move_file(dest, operation)
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\library\models.py", line 1049, in move_file
    util.move(self.path, dest)
  File "C:\Users\Henry\AppData\Local\pipx\pipx\venvs\beets\Lib\site-packages\beets\util\__init__.py", line 520, in move
    with open(syspath(path), "rb") as f:
         ^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '\\\\?\\E:\\Incoming\\Mindscape – Black Lotus (2007) {CITRUSCD002} [FLAC]\\CD  01 (Unmixed)\\01 Mindscape & Jade & Hydro - Black Lotus (Break Remix).flac'

I've gotten this issue several times importing files with beets installed at commit 6dbee24

I'll try finishing the rest of this import session with non-threaded and see what happens.