[Veedrac]

> Because the domain and range of transducers are both reducing functions, they can be chained through function composition. A chain is actually applied by transforming a reducing function then using that function to `reduce` (Rust `fold`) a collection.

For iterators:

Because the domain and range of iterator adaptors are both iterators, they can be chained through function composition. A chain is actually applied by transforming an iterator adaptor then using that iterator adaptor to "iterate" a collection.