code: public static <X extends Exception> void runInFiberChecked(SuspendableRunnable target, Class<X> exceptionType) throws X, InterruptedException {
          FiberUtil.runInFiberChecked(target, exceptionType);
      }
docs: Runs an action in a new fiber and awaits the fiber's termination.
  Unlike {@link #runInFiber(SuspendableRunnable)  runInFiber} this method does not throw {@link ExecutionException}, but wraps
  any checked exception thrown by the operation in a {@link RuntimeException}, unless it is of the given {@code exception type}, in
  which case the checked exception is thrown as-is.
  The new fiber is scheduled by the {@link DefaultFiberScheduler default scheduler}.
  
  @param target        the operation
  @param exceptionType a checked exception type that will not be wrapped if thrown by the operation, but thrown as-is.
  @throws InterruptedException