minimal thread safety
test : get file store from path
add TODOs in fs implementation
bootstrap efficient testing with isolated provider

- all tests in provider test use an isolated provider
- we ensure that static instance of provider is not in a stale state after test execution
- create memory path (not yet tested yet)
start implementing memory path

- requires a ref to fs impl, which is not really required to
get path and/or uri, however this will probably be useful later
for path resolution from/to actual fs