Fsspec: Convert async methods that open sync file handles to use LocalStore

[kylebarron]

Async functions should not open files with blocking methods like open.

obstore/obstore/python/obstore/fsspec.py

Lines 195 to 198 in 9ca85e7

	# TODO: convert to use async file system methods using LocalStore
	# Async functions should not open files with blocking methods like `open`
	with open(lpath, "rb") as f: # noqa: ASYNC230
	await obs.put_async(self.store, rpath, f)

obstore/obstore/python/obstore/fsspec.py

Lines 201 to 206 in 9ca85e7

	# TODO: convert to use async file system methods using LocalStore
	# Async functions should not open files with blocking methods like `open`
	with open(lpath, "wb") as f: # noqa: ASYNC230
	resp = await obs.get_async(self.store, rpath)
	async for buffer in resp.stream():
	f.write(buffer)

Instead we should use something like:

    async def _put_file(
        self,
        lpath: str,
        rpath: str,
        mode: str = "overwrite",  # noqa: ARG002
        **_kwargs: Any,
    ) -> None:
        local_store = LocalStore("/")
        local_file = await obs.get_async(local_store, lpath)
        await obs.put_async(self.store, rpath, local_file)

• We may want to cache the construction of LocalStore("/")? It looks like constructing that only takes 1.22 μs on my machine, so maybe not important.

• It looks like the leading "/" on a path is not an issue. I.e. this works even though there's a leading "/" in the path:

  lpath = "/Users/kyle/github/developmentseed/obstore/README.md"
  local_store = LocalStore("/")
  local_file = obs.get(local_store, lpath)
  print(local_file.bytes().to_bytes().decode())

• This may deadlock in the case that the async implementation is used synchronously, but that's something we can come back to in the future.