Is `FnMut() + Clone + Send` strictly more expressive than `Fn() + Sync`?

The context is a feature request for the Paralight iterator library: Accept `FnMut() + Clone + Send` instead of `Fn() + Sync` in `ParallelIterator` and similar APIs · Issue #27 · gendx/paralight · GitHub. For iterator combinators like .map(), the current API accepts functions that implement Fn() + Sync, for example: ParallelIteratorExt in paralight::iter - Rust. However, @discreaminant2809 pointed out that FnMut() + Clone + Send is more expressive, in that any f implementing Fn() + Sync can be ...