A new, more efficient BSON visitor was introduced in RUST-1132 for deserializing into raw documents and arrays. We discussed removing the already-existing RawBsonVisitor and using the new SeededVisitor in its place when implementing the latter, but decided not to due to the complexities involved (see here for more details). We should revisit this idea in the future, though, and consider removing the regular BsonVisitor in favor of the SeededVisitor as well to improve performance.

Using the seeded visitor for regular documents may address the stack overflows described in this issue: https://github.com/mongodb/bson-rust/issues/385