public static <T, E extends Exception> CompletableFuture<T> toCompletableFuture(ThrowableComputable<? extends T, E> provider) {
    try {
      return completedFuture(provider.compute());
    }
    catch (Exception e) {
      return CompletableFuture.failedFuture(e);
    }
  }
public static <T, E extends Exception> CompletableFuture<T> toCompletableFuture(ThrowableComputable<? extends T, E> provider)