Span

A blender::Span<T> (source) references an array that is owned by someone else. It is just a pointer and a size. Since it is so small, it should generally be passed by value.

Span is the main way to pass multiple elements into a function and should be preferred over e.g. const Vector & because it gives the caller more flexibility.

The memory directly referenced by the span is considered to be const. This is different from std::span where constness is not the default. When non-constness is required, a MutableSpan can be used. This also makes the intention more clear.