docs: public boolean deleteWatcher(String name, Watcher watcher){
          if(LOGGER.isTraceEnabled()){
              LOGGER.trace("Delete a watcher, name={}", name);
          }
          synchronized(watchers){
  
              if (watchers.containsKey(name)) {
                  return watchers.get(name).remove(watcher);
              }
          }
          return false;
      }