docs: public String getRsHost(RegionReqInfo regionReqInfo) {
          RegionInfo info = queryRegionInfo(regionReqInfo);
          if (info == null) {
              return super.getRsHost(regionReqInfo);
          }
          Region region = this.inferDomainsMap.get(info.srcUpHosts.get(0));
          if (region != null) {
              return region.getRsHost(regionReqInfo);
          } else {
              return super.getRsHost(regionReqInfo);
          }
      }