Default method for RemoteConnection.submitAsync throws exception from submit on calling thread instead of failing the future

If a RemoteConnection implementation does not override submitAsync, the default method is used which simply wraps submit in a future.

One downside of this is that if an exception is thrown by submit, the exception is thrown on the calling thread instead of failing the future.

Failing the future would be more preferable for consistencies sake, otherwise client code would need to consider that an exception could be thrown on the calling thread or that the future may fail.