code: func (c *Client) ValidateAddressAsync(address btcutil.Address) FutureValidateAddressResult {
  	addr := address.EncodeAddress()
  	cmd := btcjson.NewValidateAddressCmd(addr)
  	return c.sendCmd(cmd)
  }
docs: // ValidateAddressAsync 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 ValidateAddress for the blocking version and more details.