putCustomField method
Implementation
putCustomField(String displayName, String value) {
var customMap = {
'value': value,
'display_name': displayName,
'variable_name':
displayName.toLowerCase().replaceAll(new RegExp(r'[^a-z0-9 ]'), "_")
};
this._customFields!.add(customMap);
this._hasMeta = true;
}