Unused import in nightly rust

[XiangpengHao]

Describe the bug

With this pr been merged to nightly rust: rust-lang/rust#117772
The tracking for unused import has been improved, resulting numerous compiler warnings when building arrow-rs with nightly rust.

To Reproduce

rustup default nightly
cargo check

Expected behavior

Additional context

[XiangpengHao]

Maybe it should be a feature request not bug...

[Kikkon]

Hi, @tustvold . Following the above method. I have reproduced the issue on my machine, and there are over 40 warnings. I think i can submit a pull request to clean up these unused import ?

[tustvold]

I believe this is already being worked on in #5477

[tustvold]

label_issue.py automatically added labels {'parquet'} from #5477

[tustvold]

label_issue.py automatically added labels {'arrow'} from #5477

[tustvold]

label_issue.py automatically added labels {'arrow-flight'} from #5477

[tustvold]

label_issue.py automatically added labels {'parquet-derive'} from #5477