Circular Vec

This provides a struct called CircularVec. It is a fixed length Vec that provides a next function, which iterates through the vec. When it hits the end, instead of returning None, we just loop back to the start.

Note: This struct could use a lot of love. While I do have a need for this struct, and I use this for a personal project, this is also to become familiar with publishing a crate to crates.io. See the many ways this could be improved below.

Future work

• This is likely not as efficient as it could be. We use Vec internally, which can grow, but we don't need that.
• We could export a version of this that can change size. Shrink semantics TBA.
• This doesn't implement many traits that it could. See the traits that Vec implements for inspiration.
• The API could probably use some love, like exposing this as an iterator instead of providing a next function.
• Probably much much more.