code: @SuppressWarnings("PMD.GuardLogStatement")
      public void remove(Object obj) {
          synchronized (this) {
              running -= 1;
              if (generators != null) {
                  generators.remove(obj);
                  generatorTracking.finest(() -> "Removed generator " + obj
                      + ", " + generators.size() + " generators registered: "
                      + generators.keySet());
              }
              if (running == 0) {
                  generatorTracking
                      .finest(() -> "Zero generators, notifying all.");
                  keepAlive.interrupt();
                  notifyAll();
              }
          }
      }
docs: Removes the generator.
  
  @param obj the generator