update code to support brotli

core/config/config_cache_stats.cc

@@ -0,0 +1,13 @@
+#include <atomic>
+
+// Forward declaration of CacheStats struct
+struct CacheStats {
+    static std::atomic<uint64_t> hits;
+    static std::atomic<uint64_t> misses;
+    static bool tracking_enabled;
+};
+
+// Define static members for cache statistics
+std::atomic<uint64_t> CacheStats::hits{0};
+std::atomic<uint64_t> CacheStats::misses{0};
+bool CacheStats::tracking_enabled = false;