We can't currently update the S3 SDK because we don't support the new "Flexible Checksums" feature. This RFC describes this new feature and details how we should implement it in `smithy-rs`.
Smithy provides a [sensitive trait](https://awslabs.github.io/smithy/1.0/spec/core/documentation-traits.html#sensitive-trait) which exists as a `@sensitive` field annotation syntactically and has the following semantics: