code: public static <T>CompletableFuture<T> completedExceptionally(Throwable cause) {
  		CompletableFuture<T> result = new CompletableFuture<>();
  		result.completeExceptionally(cause);
  
  		return result;
  	}
docs: Returns an exceptionally completed {@link CompletableFuture}.
  
  @param cause to complete the future with
  @param <T> type of the future
  @return An exceptionally completed CompletableFuture