presto-iceberg/src/main/java/io/prestosql/plugin/iceberg/TypeConverter.java/TypeConverter/fromRow
class TypeConverter:    private static org.apache.iceberg.types.Type fromRow(RowType type)
    {
        List<Types.NestedField> fields = new ArrayList<>();
        for (RowType.Field field : type.getFields()) {
            String name = field.getName().orElseThrow(() ->
                    new PrestoException(NOT_SUPPORTED, "Row type field does not have a name: " + type.getDisplayName()));
            fields.add(Types.NestedField.required(fields.size() + 1, name, toIcebergType(field.getType())));
        }
        return Types.StructType.of(fields);
    }