src/GeneratorCollection.php
public function flatMap(callable $callback, $depth = INF): CollectionInterface
    {
        return $this->map($callback)->flatten($depth);
    }
public function flatMap(callable $callback, $depth = INF): CollectionInterface
    {
        return $this->map($callback)->flatten($depth);
    }
public function flatMap ( callable $ callback , $ depth = INF ) : CollectionInterface { return $ this -> map ( $ callback ) -> flatten ( $ depth ) ; }
Map then flatten
@param callable $callback
@param $depth
@return \Buttress\Collection\CollectionInterface
Map then flatten