kvserverpb: add admitted vectors to raft request/batch

Epic: none
Release note: none

pkg/kv/kvserver/kvserverpb/raft.proto

@@ -104,10 +104,15 @@ message RaftMessageRequest {
   // priority of the Entries in the Message are overridden to be
   // raftpb.LowPri.
   bool low_priority_override = 13;
+  // AdmittedState annotates a MsgAppResp message with a vector of admitted log
+  // indices. Used only with RACv2.
+  kv.kvserver.kvflowcontrol.kvflowcontrolpb.AdmittedState admitted_state = 14 [(gogoproto.nullable) = false];
 
   // AdmittedResponse is used in RACv2, for piggybacking MsgAppResp messages
   // from a follower to a leader, that advance admitted for a follower.
-  repeated kv.kvserver.kvflowcontrol.kvflowcontrolpb.AdmittedResponseForRange admitted_response = 14 [(gogoproto.nullable) = false];
+  //
+  // TODO(pav-kv): remove.
+  repeated kv.kvserver.kvflowcontrol.kvflowcontrolpb.AdmittedResponseForRange admitted_response = 15 [(gogoproto.nullable) = false];
   reserved 10;
 }
 
@@ -153,6 +158,10 @@ message RaftMessageRequestBatch {
   // provide a disjointness guarantee to leader leases.
   util.hlc.Timestamp now = 3 [(gogoproto.nullable) = false,
     (gogoproto.casttype) = "github.com/cockroachdb/cockroach/pkg/util/hlc.ClockTimestamp"];
+
+  // AdmittedStates contains admitted vector messages addressed to replicas
+  // located on the receiver node of this batch.
+  repeated kv.kvserver.kvflowcontrol.kvflowcontrolpb.PiggybackedAdmittedState admitted_states = 4 [(gogoproto.nullable) = false];
 }
 
 message RaftMessageResponseUnion {