public function __construct( $step = 1 ) {

		$this->step = $step;

		if ( has_filter( "pum_batch_per_step_{$this->batch_id}" ) ) {
			/**
			 * Filters the number of items to process per step for the given batch process.
			 *
			 * The dynamic portion of the hook name, `$this->export_type` refers to the export
			 * type defined in each sub-class.
			 *
			 * @param int $per_step The number of items to process for each step. Default 100.
			 * @param PUM_Abstract_Batch_Process $this Batch process instance.
			 */
			$this->per_step = apply_filters( "pum_batch_per_step_{$this->batch_id}", $this->per_step, $this );
		}
	}