@After
    public void tearDown() throws Exception {
        // LoggerFactoryFriend.reset();
        // System.clearProperty(SimpleLogger.LOG_FILE_KEY);
        System.setErr(oldOut);
    }
Tests that output in multithreaded environments is not mingled.

See also https://jira.qos.ch/browse/SLF4J-515
slf4j-simple/src/test/java/org/slf4j/simple/multiThreadedExecution/MultithereadedExecutionTest.java