gfe-relnote: Let GFE be able to use LIFO write scheduler in QUIC and enable it via a connection option LIFO. Protected by gfe2_reloadable_flag_quic_use_lifo_write_scheduler.

PiperOrigin-RevId: 261741584
Change-Id: I2db660dd8a9e2eb40b70147ea829825a8f45404e
diff --git a/quic/core/crypto/crypto_protocol.h b/quic/core/crypto/crypto_protocol.h
index 0facf00..bbd0b18 100644
--- a/quic/core/crypto/crypto_protocol.h
+++ b/quic/core/crypto/crypto_protocol.h
@@ -201,6 +201,8 @@
 const QuicTag kH2PR = TAG('H', '2', 'P', 'R');  // HTTP2 priorities.
 const QuicTag kFIFO = TAG('F', 'I', 'F', 'O');  // Stream with the smallest ID
                                                 // has the highest priority.
+const QuicTag kLIFO = TAG('L', 'I', 'F', 'O');  // Stream with the largest ID
+                                                // has the highest priority.
 
 // Proof types (i.e. certificate types)
 // NOTE: although it would be silly to do so, specifying both kX509 and kX59R