Add QUIC connection options `MCS4` and `MCS5` to add more options to adjust GFE allowed max concurrent streams.
These options will be used in Finch experiments to find out the optimal config value for max concurrent streams.
Protected by FLAGS_quic_reloadable_flag_quic_adjust_max_streams_allowed_via_copt2.
PiperOrigin-RevId: 565689106
diff --git a/quiche/quic/core/crypto/crypto_protocol.h b/quiche/quic/core/crypto/crypto_protocol.h
index 157e2d3..9efae96 100644
--- a/quiche/quic/core/crypto/crypto_protocol.h
+++ b/quiche/quic/core/crypto/crypto_protocol.h
@@ -466,6 +466,8 @@
const QuicTag kMCS1 = TAG('M', 'C', 'S', '1');
const QuicTag kMCS2 = TAG('M', 'C', 'S', '2');
const QuicTag kMCS3 = TAG('M', 'C', 'S', '3');
+const QuicTag kMCS4 = TAG('M', 'C', 'S', '4');
+const QuicTag kMCS5 = TAG('M', 'C', 'S', '5');
constexpr QuicTag kBSUS = TAG('B', 'S', 'U', 'S'); // Blocks server connection
// until the SETTINGS frame
