message: don't do a hashmap lookup while iterating the hashmap
diff: @@ -563,9 +563,13 @@ const DebugServer::MaterialRecord* DebugServer::getRecord(const MaterialKey& key
  void DebugServer::updateActiveVariants() {
  if (mQueryCallback) {
  - for (auto& pair : mMaterialRecords) {
  - VariantList& result = mMaterialRecords[pair.first].activeVariants;
  - mQueryCallback(pair.second.userdata, &result);
  + auto curr = mMaterialRecords.begin();
  + auto end = mMaterialRecords.end();
  + while (curr != end) {
  + auto& value = curr.value();
  + VariantList& result = value.activeVariants;
  + mQueryCallback(value.userdata, &result);
  + ++curr;
  }
  }
  }
  