aleksraiden/mt-manager ? reverse-engineered prompt

Build me a Go library for managing multiple Merkle trees in memory, with a single manager that can create, look up, and update separate trees for things like accounts and orders.

I want fast concurrent reads and writes, batch insert and delete support, and a way to compute each tree’s root plus one global root across all trees. It should support snapshotting the full state to disk so I can save and restore later, and I’d like both synchronous and async snapshot creation. Use a clean design that keeps memory use low and avoids blocking as much as possible.

Please include a small example app or simple main file that shows how to define a data type with a key and serialization, add records, fetch them back, and print the root hash. Add tests and a few benchmarks too, and if you need to check anything about the latest Go or storage docs online, go ahead and look it up.