@Override
    public RowMapper<T> specialize(ResultSet rs, StatementContext ctx) throws SQLException {
        final RowMapper<T> newDelegate = delegate.specialize(rs, ctx);
        if (newDelegate instanceof NullDelegatingMapper) {
            return newDelegate;
        } else {
            return new NullDelegatingMapper<>(index, newDelegate);
        }
    }
Delegating mapper that implements the &#0064;PropagateNull semantics to check a specific column in the result set for null first. If that column is null,
return null as the value, otherwise executed the delegated mapper.

@param <T> The generic type for the row mapper.
core/src/main/java/org/jdbi/v3/core/mapper/reflect/internal/NullDelegatingMapper.java