gfe-relnote: In GFE, export number of QUIC packets written per write operation. Protected by FLAGS_quic_export_server_num_packets_per_write_histogram.

PiperOrigin-RevId: 249251940
Change-Id: Ie92306bb1d10dec11c2801353026b363f3046d81
diff --git a/quic/core/quic_packet_creator.h b/quic/core/quic_packet_creator.h
index 259b577..06acfbe 100644
--- a/quic/core/quic_packet_creator.h
+++ b/quic/core/quic_packet_creator.h
@@ -273,6 +273,9 @@
   // connection ID lengths do not change.
   QuicPacketLength GetGuaranteedLargestMessagePayload() const;
 
+  // Packet number of next created packet.
+  QuicPacketNumber NextSendingPacketNumber() const;
+
   void set_debug_delegate(DebugDelegate* debug_delegate) {
     debug_delegate_ = debug_delegate;
   }