I build the asset bundle without BuildAssetBundleOptions.ForceRebuildAssetBundle, so each time I invoke the BuildPipeline.BuildAssetBundles only a part of asset bundle is actual build. I add a post process to encrypt the built asset bundles. Each time I get the AssetBundleManifest from the BuildPipeline.BuildAssetBundles and encrypt all asset bundles. But there has a problem, the old asset bundle that not built will encrypt twice, that will make I encrypt one file more than one times, and that make a incorrect result. Is there any way to find out which asset bundle is new build when I invoke the BuildPipeline.BuildAssetBundles?