Several of the libfuse low-level functions take a userdata param, but fusell always sets this to None: https://github.com/fusepy/fusepy/blob/master/fusell.py#L498.

Is there a way to set this that I've missed, or would it make sense to allow FUSELL.__init__() to take this as a param and pass it to libfuse? I'm happy to submit a PR if this approach makes sense.

What I'm trying to accomplish is passing custom arguments to my class that inherits from FUSELL, maybe there is a better way to accomplish this?