fetch_entry

# File activesupport/lib/active_support/cache/strategy/local_cache.rb, line 77
          def fetch_entry(key, options = nil) # :nodoc:
            entry = @data.fetch(key) { @data[key] = yield }
            dup_entry = entry.dup
            dup_entry&.dup_value!
            dup_entry
          end