code: public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier) {
      return asyncSupplyStage(ASYNC_POOL, supplier);
    }
docs: Returns a new CompletableFuture that is asynchronously completed by a task running in the
  {@link ForkJoinPool#commonPool()} with the value obtained by calling the given Supplier.
  
  @param supplier a function returning the value to be used to complete the returned
  CompletableFuture
  @param <U> the function's return type
  @return the new CompletableFuture