A bit more messing around.

metadata_reader.zig

@@ -0,0 +1,11 @@
+const std = @import("std");
+
+const MetadataHeader = packed struct {
+    compressed: bool,
+    size: u15,
+};
+
+const MetadataReader = struct {
+    rdr: std.io.AnyReader,
+    curBlock: []const u8,
+};