void close() throws IOException {
   if (keventArray != null) {
     keventArray.free();
     keventArray = null;
   }
   if (kq >= 0) {
     FileDispatcherImpl.closeIntFD(kq);
     kq = -1;
   }
 }
 void closeDevPollFD() throws IOException {
   FileDispatcherImpl.closeIntFD(wfd);
   pollArray.free();
   updatePollArray.free();
 }