PR 2.1 — Tidy: Replace Guava Maps.newConcurrentMap() in RuleBasedSegmentCacheInMemoryImp

Replace com.google.common.collect.Maps.newConcurrentMap() with
new ConcurrentHashMap<>() so this class can be extracted to
storage-commons without a Guava dependency.

AI-Session-Id: fc79892b-4019-43bf-bb4b-1b5865d3533e
AI-Tool: claude-code
AI-Model: unknown

Author: gthea

client/src/main/java/io/split/storages/memory/RuleBasedSegmentCacheInMemoryImp.java

@@ -1,6 +1,5 @@
 package io.split.storages.memory;
 
-import com.google.common.collect.Maps;
 import io.split.engine.experiments.ParsedRuleBasedSegment;
 import io.split.storages.RuleBasedSegmentCache;
 
@@ -11,6 +10,7 @@
 import java.util.List;
 import java.util.Set;
 import java.util.ArrayList;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.stream.Collectors;
@@ -29,7 +29,7 @@ public RuleBasedSegmentCacheInMemoryImp() {
     }
 
     public RuleBasedSegmentCacheInMemoryImp(long startingChangeNumber) {
-        _concurrentMap = Maps.newConcurrentMap();
+        _concurrentMap = new ConcurrentHashMap<>();
         _changeNumber = new AtomicLong(startingChangeNumber);
     }