private static String traceToString(Throwable thrown) {
        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
        thrown.printStackTrace(new PrintStream(buffer));
        return buffer.toString(UTF_8);
    }
@author valerijf
@author jonmv
@author mortent
vespa-osgi-testrunner/src/main/java/com/yahoo/vespa/testrunner/TestRunnerHandler.java