void unregisterSubmission(@Nullable String startTrace) {
    myCount.decrementAndGet();
    Map<String, Integer> traces = myTraces;
    if (startTrace != null && traces != null) {
      traces.compute(startTrace, (__, i) -> i == null || i.intValue() == 1 ? null : i - 1);
    }
  }
void unregisterSubmission(@Nullable String startTrace)