isEqual method
Implementation
isEqual(OutputModel other) {
bool scriptOk = script == null && other.script == null;
if (script != null && other.script != null) {
scriptOk = hex.encode(Uint8List.view(script!.buffer)) ==
hex.encode(Uint8List.view(other.script!.buffer));
}
return ((scriptOk && value == other.value && address == other.address));
}