code: func (c *Client) ListUnspentMinAsync(minConf int) FutureListUnspentResult {
  	cmd := btcjson.NewListUnspentCmd(&minConf, nil, nil)
  	return c.sendCmd(cmd)
  }
docs: // ListUnspentMinAsync returns an instance of a type that can be used to get
  // the result of the RPC at some future time by invoking the Receive function
  // on the returned instance.
  //
  // See ListUnspentMin for the blocking version and more details.