Bound native fragment caching and collapse concurrent page renders

app/models/fragment_cache.rb

@@ -0,0 +1,9 @@
+# Native view caches share one byte budget across every database generation.
+class FragmentCache
+  STORE = ActiveSupport::Cache::MemoryStore.new(size: 64.megabytes)
+  private_constant :STORE
+
+  def self.store
+    STORE
+  end
+end