WPF Parallelization fails

There have been reports of the mpire distributed WPF optimization failing with errors like

AttributeError: Can't pickle local object 'WholePatternFit._fit_distributed.<locals>.f

This appears to only affect Windows systems.

I think the fix is to enable dill serialization:
https://github.com/py4dstem/py4DSTEM/blob/113763791edae292060eaf817216eda7d289d352/py4DSTEM/process/wholepatternfit/wpf.py#L748-L753
should be modified to become:

        with WorkerPool(
            n_jobs=num_jobs,
            shared_objects=fit_opts,
            use_dill=True,
        ) as pool:

mpire produces threads differently on Windows vs UNIX and so there can be serialization errors that only show up one one platform when transmitting complicated objects to threads. Unfortunately I do not have a Windows machine to test this on at the moment, so someone else will have to try this and let us know.

Start in py4DSTEM/process/wholepatternfit/wpf.py at the WorkerPool setup around lines 748-753 and review how the distributed WPF fit is serialized. Apply the proposed serialization setting, then run the distributed WPF optimization on Windows. Done means the fit completes without the reported local-object pickle error.