feat(tvix/store/fuse): implement open explicitly r/6435

This "reverts" commit 9f600de22671ee1f88e6fb9e53a5a385b434871b (the
initial revert of f5e291cf8328096d790f5416cf1968cb9164220a).

Now with BlobService returning a BlobReader that implements io::Seek, we
can actually just call blob_reader.seek(io::SeekFrom::Start(offset as
u64)).

This means, we currently will fail to seek backwards inside a file.

Change-Id: I9c19448df6831a3537252f99210374f2126ecfc0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8886
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: raitobezarius <tvl@lahfa.xyz>

0 files changed, 0 insertions, 0 deletions