Implement LogMeta#toString to easily debug zookeeper log removal wa…

…rnings (#1070)

**Motivation**

With the improvement introduced by #1040, we have been observing logs where CentralDogma attempts to delete logs that don't exist.

In order to 1) verify which nodes are being prematurely deleted and 2) to observe trends as to why this may occur, I propose that `LogMeta#toString` be implemented.

.github/workflows/actions_build.yml

@@ -28,7 +28,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-12, windows-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         java: [21]
         include:
           - java: 8

server/src/main/java/com/linecorp/centraldogma/server/internal/replication/ZooKeeperCommandExecutor.java

@@ -83,6 +83,7 @@
 import com.github.benmanes.caffeine.cache.Caffeine;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Joiner;
+import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMultimap;
 import com.google.common.escape.Escaper;
@@ -1203,6 +1204,16 @@ List<Long> blocks() {
         public void appendBlock(long blockId) {
             blocks.add(blockId);
         }
+
+        @Override
+        public String toString() {
+            return MoreObjects.toStringHelper(this)
+                              .add("replicaId", replicaId)
+                              .add("timestamp", timestamp)
+                              .add("size", size)
+                              .add("blocks", blocks)
+                              .toString();
+        }
     }
 
     private long storeLog(ReplicationLog<?> log) {