message: Delete outdated comment
  `metadata_` is now guarded by absl locks and lock annotations were
  also added by
diff: @@ -86,9 +86,6 @@ public:
  // endpoints churning during a deploy of a large cluster). A possible improvement
  // would be to use TLS and post metadata updates from the main thread. This model would
  // possibly benefit other related and expensive computations too (e.g.: updating subsets).
  - //
  - // TODO(rgs1): we should move to absl locks, once there's support for R/W locks. We should
  - // also add lock annotations, once they work correctly with R/W locks.
  const std::shared_ptr<envoy::api::v2::core::Metadata> metadata() const override {
  absl::ReaderMutexLock lock(&metadata_mutex_);
  return metadata_;
  