docs: public static OpenRtbJsonFactory registerAdxExt(OpenRtbJsonFactory factory) {
      return factory
          .register(new BidRequestExtReader(), BidRequest.Builder.class)
          .register(new BidRequestExtWriter(), BidRequestExt.class, BidRequest.class)
          .register(new ImpExtReader(), Imp.Builder.class)
          .register(new ImpExtWriter(), ImpExt.class, Imp.class)
          .register(new BidExtReader(), Bid.Builder.class)
          .register(new BidExtWriter(), BidExt.class, Bid.class)
          .register(new BidResponseExtReader(), BidResponse.Builder.class)
          .register(new BidResponseExtWriter(), BidResponseExt.class, BidResponse.class)
          .register(new SiteExtReader(), Site.Builder.class)
          .register(new SiteExtWriter(), SiteExt.class, Site.class)
          .register(new AppExtReader(), App.Builder.class)
          .register(new AppExtWriter(), AppExt.class, App.class)
          .register(new NativeRequestExtReader(), NativeRequest.Builder.class)
          .register(new NativeRequestExtWriter(), NativeRequestExt.class, NativeRequest.class)
          .register(new UserExtReader(), User.Builder.class)
          .register(new UserExtWriter(), UserExt.class, User.class)
          .register(new RegsExtReader(), Regs.Builder.class)
          .register(new RegsExtWriter(), RegsExt.class, Regs.class)
          .register(new EventTrackerExtReader(), EventTracker.Builder.class)
          .register(new EventTrackerExtWriter(), EventTrackerExt.class, EventTracker.class);
    }