relnote: Add a new LazyFack loss detection to QUIC triggered by the LFAK connection option.

net/quic/core/quic_sent_packet_manager.cc

Index: net/quic/core/quic_sent_packet_manager.cc
diff --git a/net/quic/core/quic_sent_packet_manager.cc b/net/quic/core/quic_sent_packet_manager.cc
index c38db4c754877cab3dfe28698576ab3faa1016e1..aacceb157310085b9c99ef0c8aeab0242b7eeece 100644
--- a/net/quic/core/quic_sent_packet_manager.cc
+++ b/net/quic/core/quic_sent_packet_manager.cc
@@ -152,6 +152,11 @@ void QuicSentPacketManager::SetFromConfig(const QuicConfig& config) {
       ContainsQuicTag(config.ReceivedConnectionOptions(), kATIM)) {
     general_loss_algorithm_.SetLossDetectionType(kAdaptiveTime);
   }
+  if (FLAGS_quic_enable_lazy_fack &&
+      config.HasReceivedConnectionOptions() &&
+      ContainsQuicTag(config.ReceivedConnectionOptions(), kLFAK)) {
+    general_loss_algorithm_.SetLossDetectionType(kLazyFack);
+  }
   if (config.HasClientSentConnectionOption(kUNDO, perspective_)) {
     undo_pending_retransmits_ = true;
   }