# File lib/active_record/fiber_patches.rb, line 100
      def clear_stale_cached_connections!
        cache = @reserved_connections
        keys = Set.new(cache.keys)

        ActiveRecord::ConnectionAdapters.fiber_pools.each do |pool|
          pool.busy_fibers.each_pair do |object_id, fiber|
            keys.delete(object_id)
          end
        end

        keys.each do |key|
          next unless cache.has_key?(key)
          checkin cache[key]
          cache.delete(key)
        end
      end