public String getStackTrace() {
        var stackTrace = new StringBuilder();

        StackTraceElement[] elements = thread.getStackTrace();
        for (int i = 0; i < elements.length; ++i) {
            var element = elements[i];
            stackTrace.append(element.getClassName())
                    .append('.')
                    .append(element.getMethodName())
                    .append('(')
                    .append(element.getFileName())
                    .append(':')
                    .append(element.getLineNumber())
                    .append(")\n");
        }

        return stackTrace.toString();
    }
Non-empty if there is an ongoing recording for this thread.
zkfacade/src/main/java/com/yahoo/vespa/curator/stats/ThreadLockStats.java