docs: public K getCurrentKey()
      {
          lock.lock();
          try
          {
              Thread currentThread = Thread.currentThread();
              for (Entry<K,Thread> entry : threadMap.entrySet())
              {
                  if (currentThread.equals(entry.getValue()))
                  {
                      return entry.getKey();
                  }
              }
              return null;
          }
          finally
          {
              lock.unlock();
          }
      }