Field<R, W extends Object?> typedef
Field<R, W extends Object?> =
W Function(R)
Row field getter for schema R.
Use W such that null is W matches the column's nullability
(int vs int?, ColumnType<int> vs ColumnType<int?>).
It's inferred from the accessor's return type and drives
Column.isNullable.
Implementation
typedef Field<R, W extends Object?> = W Function(R);