code: func (cfg *BuildCfg) shouldRender(p *pageState) bool {
  	if !p.render {
  		return false
  	}
  	if p.forceRender {
  		return true
  	}
  
  	if len(cfg.RecentlyVisited) == 0 {
  		return true
  	}
  
  	if cfg.RecentlyVisited[p.RelPermalink()] {
  		return true
  	}
  
  	if cfg.whatChanged != nil && !p.File().IsZero() {
  		return cfg.whatChanged.files[p.File().Filename()]
  	}
  
  	return false
  }
docs: // shouldRender is used in the Fast Render Mode to determine if we need to re-render
  // a Page: If it is recently visited (the home pages will always be in this set) or changed.
  // Note that a page does not have to have a content page / file.
  // For regular builds, this will allways return true.
  // TODO(bep) rename/work this.