private static Streamer createStreamer(boolean allowJacksonIfAvailable, GsonOptions options) {
    if (allowJacksonIfAvailable) {
      try {
        return new JacksonStreamer(options);
      } catch (Throwable ex) {
        // cannot load jackson streamer class, fallback to default
      }
    }
    return new GsonStreamer(options);
  }
Creates new provider with flexible setup.
@param options options for provider
gson/src/org/immutables/gson/stream/GsonMessageBodyProvider.java