mapOrNull<TResult extends Object?>  method 
    Null safety
- TResult? $default(- _DataRow value
 
- {TResult? byIndex(- DataRowByIndex value
 
@optionalTypeArgs, inherited
    Implementation
@optionalTypeArgs
TResult? mapOrNull<TResult extends Object?>(
  TResult? Function(_DataRow value)? $default, {
  TResult? Function(DataRowByIndex value)? byIndex,
}) =>
    throw _privateConstructorUsedError;