chore(tiering): Fix MacOs build (#2913)

Author: dranikpg

src/server/tiered_storage.h

@@ -149,6 +149,44 @@ class DbSlice;
 
 // This is a stub implementation for non-linux platforms.
 namespace dfly {
+
+// Manages offloaded values
+class TieredStorageV2 {
+  class ShardOpManager;
+
+  const static size_t kMinValueSize = tiering::kPageSize / 2;
+
+ public:
+  explicit TieredStorageV2(DbSlice* db_slice) {
+  }
+
+  TieredStorageV2(TieredStorageV2&& other) = delete;
+  TieredStorageV2(const TieredStorageV2& other) = delete;
+
+  std::error_code Open(std::string_view path) {
+  }
+
+  void Close() {
+  }
+
+  // Read offloaded value. It must be of external type
+  util::fb2::Future<std::string> Read(std::string_view key, const PrimeValue& value) {
+    return {};
+  }
+
+  // Stash value. Sets IO_PENDING flag and unsets it on error or when finished
+  void Stash(std::string_view key, PrimeValue* value) {
+  }
+
+  // Delete value. Must either have pending IO or be offloaded (of external type)
+  void Delete(std::string_view key, PrimeValue* value) {
+  }
+
+  TieredStatsV2 GetStats() {
+    return TieredStatsV2{};
+  }
+};
+
 class TieredStorage {
  public:
   static constexpr size_t kMinBlobLen = size_t(-1);  // infinity.