refUnwrapped

        fn refUnwrapped(formatter: *Formatter, node: Metadata) Allocator.Error!FormatData.Node {
            const builder = formatter.builder;
            const unwrapped_metadata = node.unwrap(builder);
            switch (unwrapped_metadata.tag(builder)) {
                .expression, .constant => return .{ .@"inline" = unwrapped_metadata },
                else => |metadata_tag| {
                    assert(!metadata_tag.isInline());
                    const gop = try formatter.map.getOrPut(builder.gpa, .{ .metadata = unwrapped_metadata });
                    return .{ .index = @intCast(gop.index) };
                },
            }
        }