Runs the CPU-heavy parts of smoldot. Must be passed a port whose other end is passed to ClientOptions.portToWorker.

Returns a Promise that is ready when the smoldot client is shut down (either because it crashes or intentionally with a call to Client.terminate). Since this function is asynchronous, this Promise is wrapped around another Promise. In other words, the outer Promise is ready when execution starts, and the inner Promise is ready when execution ends.