docs: @Deprecated
      public int createThreads(int numberOfThreads) {
  
          int ncreated = 0;
  
          for (int i = 0; i < numberOfThreads; ++i) {
              synchronized (this) {
                  if (poolSize_ < maximumPoolSize_) {
                      addThread(null);
                      ++ncreated;
                  } else
                      break;
              }
          }
  
          return ncreated;
      }