gfe-relnote: Implement QUIC MTU discovery v2. Protected by --gfe2_reloadable_flag_quic_mtu_discovery_v2.

PiperOrigin-RevId: 274290098
Change-Id: I6a55ff6aced1702fd42841f9a130f4d84076c3ec
diff --git a/quic/test_tools/quic_connection_peer.h b/quic/test_tools/quic_connection_peer.h
index f329a1c..5b97ae6 100644
--- a/quic/test_tools/quic_connection_peer.h
+++ b/quic/test_tools/quic_connection_peer.h
@@ -111,6 +111,10 @@
                                          QuicPacketCount packets);
   static void SetNextMtuProbeAt(QuicConnection* connection,
                                 QuicPacketNumber number);
+  static void ReInitializeMtuDiscoverer(
+      QuicConnection* connection,
+      QuicPacketCount packets_between_probes_base,
+      QuicPacketNumber next_probe_at);
   static void SetAckMode(QuicConnection* connection, AckMode ack_mode);
   static void SetFastAckAfterQuiescence(QuicConnection* connection,
                                         bool fast_ack_after_quiescence);