private static void writeAppenderRefFilterConfigFile(final File configFile, final Level level)
      throws IOException {
    String xml =
        "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" + "<Configuration monitorInterval=\"5\">"
            + "<Appenders>" + "<Console name=\"STDOUT\" target=\"SYSTEM_OUT\">" + "</Console>"
            + "</Appenders>" + "<Loggers>" + "<Logger name=\"" + TEST_LOGGER_NAME + "\" level=\""
            + level.name() + "\" additivity=\"true\">" + "</Logger>" + "<Root level=\"FATAL\">"
            + "<AppenderRef ref=\"STDOUT\">" + "<filters>" + "<MarkerFilter marker=\""
            + ENABLED_MARKER_NAME + "\" onMatch=\"ACCEPT\" onMismatch=\"DENY\"/>" + "</filters>"
            + "</AppenderRef>" + "</Root>" + "</Loggers>" + "</Configuration>";
    BufferedWriter writer = new BufferedWriter(new FileWriter(configFile));
    writer.write(xml);
    writer.close();
  }
Verifies FastLogger isDelegating if there is a AppenderRef Filter.

@param level the log Level
@param expectIsDelegating true if expecting FastLogger.isDelegating to be true
geode-log4j/src/integrationTest/java/org/apache/geode/logging/log4j/internal/impl/FastLoggerIntegrationTest.java