docs: @Override
     public void closeStdin(boolean force)
     {
        if (force) {
           stdinClose();
        } else {
          if (stdinClosing.compareAndSet(false, true)) {
             pendingWrites.add(pendingWriteStdinClosedTombstone);
             if (!writePending) {
                myProcessor.wantWrite(this);
             }
          } else {
             throw new IllegalStateException("closeStdin() method has already been called.");
          }
        }
     }