Trait for creating the ArrTBuilder. Instances for the ArrMapBuilder type class, for classes / traits you control, should go in the companion
object of B. The first type parameter is called B, because to corresponds to the B in
map(f: A => B): ArrB function.
BuffT can be inbuilt Jvm type like ArrayBuffer[Int] for B = Int and BB = Ints, or it can be a compile time wrapped Arraybuffer inheriting from
BuffProdHomo.
BuffT can be inbuilt Jvm type like ArrayBuffer[Int] for B = Int and BB = Ints, or it can be a compile time wrapped Arraybuffer inheriting from
BuffProdHomo.