code: public Long getTypeFirstWaitMs(ResourceType type) {
      synchronized(typeToFirstWait) {
        // Was it ever requested?
        if (!typeToFirstWait.containsKey(type)) {
          return null;
        }
        Long firstWait = typeToFirstWait.get(type);
        if (firstWait == null) {
          return ClusterManager.clock.getTime() - startTime;
        }
  
        return firstWait;
      }
    }
docs: Get the time to start (or waited so far) for the first resource of a type.
  If there is no such request, this will return null.  This is thread safe.
  
  @param type Type to check
  @return Time to start or waited so far in ms or null if not requested.