UserExporter.php

class UserExporter
{
    use CsvWriter;

    public function __construct(User $users, UserTransformer $transformer)
    {
        $this->setup();
        $this->setTransformer($transformer);
        $this->users = $users;
    }

    public function getFile()
    {
        $this->users->chunk(100, function ($users) {
            $this->writer->insertAll($users);
        });

        return $this->file;
    }
}