code: func (c *Config) LoadIteratorToDepth(ctx context.Context, qs graph.QuadStore, dst reflect.Value, depth int, list graph.Iterator) error {
  	if depth >= 0 {
  		// 0 depth means "current level only" for user, but it's easier to make depth=0 a stop condition
  		depth++
  	}
  	l := c.newLoader(qs)
  	return l.loadIteratorToDepth(ctx, dst, depth, list)
  }
docs: // LoadIteratorToDepth is the same as LoadIteratorTo, but stops at a specified depth.
  // Negative value means unlimited depth, and zero means top level only.