Make pathlib extensible

Scanning over pandas handling of gcs path it looks to make a similar assumption and expects gcs path (or s3 path/etc) to be returned from fspath. dask is another library that assumes similar and will coerce Path with fspath and later expects gs prefix/uri to be given. So I don’t think tensorflow is special here and it’s common (not only choice) for fspath to be expected to be uri.

One library that is pick something closer to your idea of not returing uri is cloudpathlib. It has interesting choice that for remote paths like gcs/s3 instead of returns gs://path for __fspath__ it copies file locally and returns the local path instead. Which can work fine for reading, but unsure that makes much sense for any write api