Add QUIC connection options `MCS1`, `MCS2` and `MCS3` 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_copt.
PiperOrigin-RevId: 535385422
diff --git a/quiche/quic/core/crypto/crypto_protocol.h b/quiche/quic/core/crypto/crypto_protocol.h
index 31937bc..99099dd 100644
--- a/quiche/quic/core/crypto/crypto_protocol.h
+++ b/quiche/quic/core/crypto/crypto_protocol.h
@@ -466,6 +466,10 @@
// Stats collection tags
const QuicTag kEPID = TAG('E', 'P', 'I', 'D'); // Endpoint identifier.
+const QuicTag kMCS1 = TAG('M', 'C', 'S', '1');
+const QuicTag kMCS2 = TAG('M', 'C', 'S', '2');
+const QuicTag kMCS3 = TAG('M', 'C', 'S', '3');
+
// clang-format on
// These tags have a special form so that they appear either at the beginning
