code: public void clear() {
          int currentCount = threadCounter.decrementAndGet();
          if (log.isLoggable(Level.FINEST)) {
              log.finest("Clear: Disassociate Thread from FragmentBuilder(1): current thread count=" + currentCount);
              synchronized (threadNames) {
                  threadNames.remove(Thread.currentThread().getName());
              }
          }
          FragmentBuilder currentBuilder = builders.get();
          if (currentBuilder != null) {
              currentBuilder.decrementThreadCount();
          }
          builders.remove();
      }
docs: This method clears the trace fragment builder for the
  current thread of execution.