code: private void initSurrogateMap(Map<String, List<String>> targetCapabilities,
              SurrogateCapabilitiesHeader surrogateCapabilitiesHeader) {
  
          for (SurrogateCapabilities sc : surrogateCapabilitiesHeader.getSurrogates()) {
              targetCapabilities.put(sc.getDeviceToken(), new ArrayList<String>());
          }
      }
docs: Populate the Map with all current devices, with empty capabilities.
  
  @param targetCapabilities
  @param surrogateCapabilitiesHeader