The tar format expects `/`, although some untar implementations do seem to handle Windows-style `\` path separators (7-Zip at least).
The tar.Writer API can't really enforce this, though, as doing so would effectively make `\` an illegal character when it's really not. So, it's up to the user to provide paths with the correct path separators.
`Build/WebServer.zig` will still output tars with `\` as a path separator on Windows, but that's currently only used during fuzzing which is not yet implemented on Windows.
When switching on an error, using the captured value instead of the original
one is always preferable since its error set has been narrowed to only
contain errors which haven't already been handled by other switch prongs.
The subsequent commits will disallow this form as an unreachable `else` prong.
This "get" is useless noise and was copied from FixedBufferWriter.
Since this API has not yet landed in a release, now is a good time
to make the breaking change to fix this.
Ryan Liptak