code: func (c *Client) NewBroker(prefix string) keyval.BytesBroker {
  	return &BrokerWatcher{
  		Client: c,
  		prefix: prefix,
  	}
  }
docs: // NewBroker creates a new instance of a proxy that provides
  // access to Bolt. The proxy will reuse the connection from Client.
  // <prefix> will be prepended to the key argument in all calls from the created
  // BrokerWatcher. To avoid using a prefix, pass keyval. Root constant as
  // an argument.