message: Make Size() function thread safe to avoid core dump
diff: @@ -257,6 +257,7 @@ uint32_t RequestInfoSet::RemoveMobileRequests() {
  }
  const size_t RequestInfoSet::Size() {
  + sync_primitives::AutoLock lock(this_lock_);
  CheckSetSizes();
  return time_sorted_pending_requests_.size();
  }
  