code: private static List<Address> getCoords(Iterable<PingData> mbrs) {
          if(mbrs == null)
              return null;
  
          List<Address> coords=null;
          for(PingData mbr: mbrs) {
              if(mbr.isCoord()) {
                  if(coords == null)
                      coords=new ArrayList<>();
                  if(!coords.contains(mbr.getAddress()))
                      coords.add(mbr.getAddress());
              }
          }
          return coords;
      }
docs: Returns all members whose PingData is flagged as coordinator