code: func (tx *Tx) DescendKeys(pattern string,
  	iterator func(key, value string) bool) error {
  	if pattern == "" {
  		return nil
  	}
  	if pattern[0] == '*' {
  		if pattern == "*" {
  			return tx.Descend("", iterator)
  		}
  		return tx.Descend("", func(key, value string) bool {
  			if match.Match(key, pattern) {
  				if !iterator(key, value) {
  					return false
  				}
  			}
  			return true
  		})
  	}
  	min, max := match.Allowable(pattern)
  	return tx.DescendLessOrEqual("", max, func(key, value string) bool {
  		if key < min {
  			return false
  		}
  		if match.Match(key, pattern) {
  			if !iterator(key, value) {
  				return false
  			}
  		}
  		return true
  	})
  }
docs: // DescendKeys allows for iterating through keys based on the specified pattern.