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

net/quic/core/crypto/crypto_protocol.h

Index: net/quic/core/crypto/crypto_protocol.h
diff --git a/net/quic/core/crypto/crypto_protocol.h b/net/quic/core/crypto/crypto_protocol.h
index 580bd187aaa04703bfa15a4a30538679fbae3ee2..cc3fdbfbab458aaf10421c38d36cd0fb70e1af50 100644
--- a/net/quic/core/crypto/crypto_protocol.h
+++ b/net/quic/core/crypto/crypto_protocol.h
@@ -106,6 +106,8 @@ const QuicTag kDHDT = TAG('D', 'H', 'D', 'T');   // Disable HPACK dynamic table.
 const QuicTag kIPFS = TAG('I', 'P', 'F', 'S');   // No Immediate Forward Secrecy
 const QuicTag kCONH = TAG('C', 'O', 'N', 'H');   // Conservative Handshake
                                                  // Retransmissions.
+const QuicTag kLFAK = TAG('L', 'F', 'A', 'K');   // Don't invoke FACK on the
+                                                 // first ack.
 
 // Optional support of truncated Connection IDs.  If sent by a peer, the value
 // is the minimum number of bytes allowed for the connection ID sent to the