Disabling ProxyToWorker option has no effect
Hello,

It seems `proxyToWorker: false` option has no effects. the library still opens a worker and even closing the wallet doesn't close the worker.
This causes for example Jest show us a warning message: "A worker process has failed to exit gracefully and has been force exited. This is likely caused by tests leaking due to improper teardown. Try running with --detectOpenHandles to find leaks. Active timers can also cause this, ensure that .unref() was called on them.".