add reply flag for misrouted requests

Summary: We will use this as a reply flag to identify client requests that are continuously get misrouted.

Reviewed By: anidev

Differential Revision: D79384027

fbshipit-source-id: 4d70d9fb1d1eb89d8014a45fd8b2a492e2b849aa

Author: Lenar Fatikhov

mcrouter/lib/mc/msg.h

@@ -267,6 +267,7 @@ enum mc_msg_flags_t {
   MC_MSG_FLAG_KEY_CLIENT_BINDING_ENABLED = 0x40,
   MC_MSG_FLAG_REQUEST_EXPTIME = 0x80,
   MC_MSG_FLAG_THRIFT_BINARY_SERIALIZED = 0x100,
+  MC_MSG_FLAG_REQUEST_MISROUTED_OR_STALE = 0x200,
   MC_MSG_FLAG_NZLIB_COMPRESSED = 0x800,
   MC_MSG_FLAG_QUICKLZ_COMPRESSED = 0x2000,
   MC_MSG_FLAG_SNAPPY_COMPRESSED = 0x4000,
@@ -308,6 +309,8 @@ static inline const char* mc_flag_to_string(const enum mc_msg_flags_t flag) {
       return "ASCII_INT_SERIALIZED";
     case MC_MSG_FLAG_THRIFT_BINARY_SERIALIZED:
       return "THRIFT_BINARY_SERIALIZED";
+    case MC_MSG_FLAG_REQUEST_MISROUTED_OR_STALE:
+      return "REQUEST_MISROUTED_OR_STALE";
     case MC_MSG_FLAG_SIZE_SPLIT:
       return "SIZE_SPLIT";
     case MC_MSG_FLAG_KEY_CLIENT_BINDING_ENABLED: