Update comments

Author: ivandika3

ratis-server/src/test/java/org/apache/ratis/LinearizableReadTests.java

@@ -88,6 +88,9 @@ public void setup() {
     RaftServerConfigKeys.Read.setOption(p, LINEARIZABLE);
     RaftServerConfigKeys.Read.setLeaderLeaseEnabled(p, isLeaderLeaseEnabled());
     RaftServerConfigKeys.Read.ReadIndex.setType(p, readIndexType());
+    // Disable dummy request since currently the request is implemented as a watch request
+    // which can cause follower client to trigger failover to leader which will cause the
+    // all reads to be sent to the leader, making the follower read moot.
     RaftClientConfigKeys.Async.Experimental.setSendDummyRequest(p, false);
   }
 

ratis-test/src/test/java/org/apache/ratis/grpc/TestLinearizableReadRepliedIndexWithGrpc.java

@@ -69,7 +69,7 @@ static <C extends MiniRaftCluster> void runTestFollowerReadOnlyParallelRepliedIn
     try (RaftClient leaderClient = cluster.createClient(leader.getId());
          RaftClient f0Client = cluster.createClient(f0);
          RaftClient f1Client = cluster.createClient(f1)) {
-      // Warm up the clients first
+      // Warm up the clients first before blocking the reply flusher
       assertReplyExact(0, leaderClient.async().sendReadOnly(QUERY).get());
       assertReplyExact(0, f0Client.async().sendReadOnly(QUERY, f0).get());
       assertReplyExact(0, f1Client.async().sendReadOnly(QUERY, f1).get());