code: public void closeall(String line, DispatchCallback callback) {
      close(null, callback);
      if (callback.isSuccess()) {
        while (callback.isSuccess()) {
          close(null, callback);
        }
        // the last "close" will set it to fail so reset it to success.
        callback.setToSuccess();
      }
      // probably a holdover of the old boolean returns.
      callback.setToFailure();
    }
docs: Closes all connections.
  
  @param line Command line
  @param callback Callback for command status