code: public static <Message> Topic<Message> singleStreamWithOffset(
              Function<Offset, Source<Pair<Message, Offset>, ?>> eventStream) {
          return taggedStreamWithOffset(SINGLETON_TAG, (tag, offset) -> eventStream.apply(offset));
      }
docs: Publish a single stream.
  
  This producer will ensure every element from the stream will be published at least once (usually only once),
  using the message offsets to track where in the stream the producer is up to publishing.
  
  @param eventStream A function to create the event stream given the last offset that was published.
  @return The topic producer.