GenTraversableOnceB

GenTraversableOnceB is a type class in Scala that represents a collection that can be traversed at most once, and it provides a single `traverseOnce` method. This method takes a function that transforms each element into an effectful computation and collects the results into a single effectful computation. The "B" in the name signifies that the resulting collection after traversal is of type B, which could be different from the original element type.

The core idea behind `GenTraversableOnceB` is to allow for efficient processing of collections where elements are consumed during iteration. This is often seen in scenarios involving streams, iterators, or other data structures where accessing an element inherently removes it or changes its state. The `traverseOnce` method is designed to be used with effect types like `Future`, `Either`, or `Option`, enabling sequential execution and error handling or asynchronous operations.

Unlike `TraversableOnce`, which focuses on producing a single result from a traversal, `GenTraversableOnceB` is about producing a collection of results within an effect. The `traverseOnce` method signature typically looks something like `def traverseOnce[G[_], B](f: A => G[B]): G[Collection[B]]`, where `G` represents the effect type and `Collection` represents the structure of the resulting collection. This allows for composability and integration with various functional programming patterns in Scala.