More Scala code

[He-Pin]

I think more Scala code can help us cross-compile to WASM or Scala native, especially when I want to build something eg, e.g., a harness system.

[pjfanning]

It's my view that if we ever do want to support Scala JS or Scala Native that we start one module at a time. For instance, aiming for pekko-actor support and then pekko-stream, etc.