code: public function save_transit_posts( $new_status, $old_status, $post ) {
  
  		$this->transit_posts[ $post->ID ] = array(
  			'old_status' => $old_status,
  			'new_status' => $new_status
  		);
  	}
docs: catch post status transition of each post
  
  @wp-hook transition_post_status
  @since 2013.07.17
  
  @param string $new_status
  @param string $old_status
  @param WP_Post $post