code: @SafeVarargs
      public static <T> Single<T> firstSuccess(Single<T>... fts) {
          return Single.fromPublisher(Future.firstSuccess(futures(fts)));
  
      }
docs: Select the first Future to return with a successful result
  
  <pre>
  {@code
  Single<Integer> ft = Single.empty();
  Single<Integer> result = Singles.firstSuccess(Single.deferred(()->1),ft);
  
  ft.complete(10);
  result.get() //1
  }
  </pre>
  
  @param fts Singles to race
  @return First Single to return with a result