code: public static String writeMultipleClientConfigAvro(Map<String, Properties> mapStoreToProps) {
          // TODO: Use a dedicated json lib. We shouldn't be manually manipulating json...
          String avroConfig = "";
          Boolean firstStore = true;
          for(String storeName: mapStoreToProps.keySet()) {
              if(firstStore) {
                  firstStore = false;
              } else {
                  avroConfig = avroConfig + ",\n";
              }
              Properties props = mapStoreToProps.get(storeName);
              avroConfig = avroConfig + "\t\"" + storeName + "\": "
                           + writeSingleClientConfigAvro(props);
  
          }
          return "{\n" + avroConfig + "\n}";
      }
docs: Assembles an avro format string that contains multiple fat client configs
  from map of store to properties
  
  @param mapStoreToProps A map of store names to their properties
  @return Avro string that contains multiple store configs