Should we seal `FileExt`, `MetadataExt` and `OpenOptionsExt`?

[ho-229]

context #118795 (comment)

[taiki-e]

See #81213 (comment) for previous discussions.

[ChrisDenton]

In summary, the results of the 2021 crater run were that it's likely ok to seal:

• FileTypeExt
• MetadataExt
• PermissionsExt

Sealing OpenOptionsExt and FileExt caused too many problems.

[ho-229]

thanks

[ho-229]

Hello everyone

Some extension traits like std::os::windows::fs::MetadataExt which contains unstable method that can't implement by user without nightly feature. And I note tokio and async_fs don't implement these extension traits nowadays.

So I think we should reconsider this issue.