code: private void print( Queue<Runnable> queue, IoEvent event) {
          StringBuilder sb = new StringBuilder();
          sb.append( "Adding event " ).append( event.getType() ).append( " to session " ).append(event.getSession().getId() );
          boolean first = true;
          sb.append( "\nQueue : [" );
          for (Runnable elem:queue) {
              if ( first ) {
                  first = false;
              } else {
                  sb.append( ", " );
              }
                  
              sb.append(((IoEvent)elem).getType()).append(", ");
          }
          sb.append( "]\n" );
          LOGGER.debug( sb.toString() );
      }
docs: A Helper class used to print the list of events being queued.