findInstancesDirViaSetup

    fn findInstancesDirViaSetup(gpa: Allocator, io: Io, registry: *Registry) error{ OutOfMemory, PathNotFound }!Dir {
        const vs_setup_key_path = L("Microsoft\\VisualStudio\\Setup");
        const vs_setup_key = registry.openSoftwareKey(.{ .root = .local_machine }, vs_setup_key_path) catch |err| switch (err) {
            error.KeyNotFound => return error.PathNotFound,
        };
        defer vs_setup_key.close();

        const packages_path = vs_setup_key.getString(gpa, .{ .name = L("CachePath") }, .wtf8) catch |err| switch (err) {
            error.NotAString,
            error.ValueNameNotFound,
            error.StringNotFound,
            => return error.PathNotFound,

            error.OutOfMemory => |e| return e,
        };
        defer gpa.free(packages_path);

        if (!std.fs.path.isAbsolute(packages_path)) return error.PathNotFound;

        const instances_path = try std.fs.path.join(gpa, &.{ packages_path, "_Instances" });
        defer gpa.free(instances_path);

        return Dir.openDirAbsolute(io, instances_path, .{ .iterate = true }) catch return error.PathNotFound;
    }