code: public static Action0 fromRunnable(Runnable run, Worker inner) {
          if (run == null) {
              throw new NullPointerException("run");
          }
          return new ActionWrappingRunnable(run, inner);
      }
docs: Converts a runnable instance into an Action0 instance.
  @param run the Runnable to run when the Action0 is called
  @return the Action0 wrapping the Runnable