code: func (c *Client) GetNewAddressAsync(account string) FutureGetNewAddressResult {
  	cmd := btcjson.NewGetNewAddressCmd(&account)
  	return c.sendCmd(cmd)
  }
docs: // GetNewAddressAsync 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 GetNewAddress for the blocking version and more details.