Decode produces an Snapshot from a stream / binary represnetation.

DecodeSnapshot fills a NodeAssembler (from `Type.Snapshot__Repr.NewBuilder()`) from a stream of bytes.

DecodeSnapshotBranch fills a NodeAssembler (from `Type.SnapshotBranch__Repr.NewBuilder()`) from a stream of bytes.

Encode serializes a git node to a raw binary form.

Type is a struct embeding a NodePrototype/Type for every Node implementation in this package.