protected PageChannel(boolean testing){
  if (!testing) {
    throw new IllegalArgumentException();
  }
  _channel=null;
  _closeChannel=false;
  _format=JetFormat.VERSION_4;
  _autoSync=false;
}

protected PageChannel ( boolean testing ) { if ( ! testing ) { throw new IllegalArgumentException ( ) ; } _channel = null ; _closeChannel = false ; _format = JetFormat . VERSION_4 ; _autoSync = false ; }
only used by unit tests
