toMap method
Creates a Map<String, dynamic> map
representation of this instance.
This can be useful for saving the instance in a database.
Implementation
Map<String, dynamic> toMap() => <String, dynamic>{
_nameKey: name,
_renewalKey: renewal.string(),
_sizeKey: '$size',
_startKey: start.toIso8601String(),
_transactionsKey: transactions.toListOfMaps(),
};