BaseReceiptCommand.from constructor
Implementation
BaseReceiptCommand.from(String text, Mapping? origin) : super.fromCmd(Command.RECEIPT) {
// text message
this['text'] = text;
// original envelope of message responding to,
// includes 'sn' and 'signature'
if (origin != null) {
assert(!(origin.isEmpty ||
origin.containsKey('data') ||
origin.containsKey('keys') ||
origin.containsKey('meta') ||
origin.containsKey('visa')), 'impure envelope: $origin');
this['origin'] = origin;
}
}