@Override
        public R map(ResultSet rs, StatementContext ctx) throws SQLException {
            T obj = construct();

            for (FieldData f : fields) {
                Object value = f.mapper.map(rs, ctx);
                boolean wasNull = (value == null || (f.isPrimitive && rs.wasNull()));
                if (f.propagateNull && wasNull) {
                    return postProcessor.apply(null);
                }
                writeField(obj, f.field, value);
            }

            return postProcessor.apply(obj);
        }
Returns a mapper for the given bean class

@param <T> the type to map
@param type the mapped class
@param prefix the column name prefix for each mapped field
@return a mapper for the given bean class
core/src/main/java/org/jdbi/v3/core/mapper/reflect/FieldMapper.java