Diff highlights in Visual Studio Code without Git

One neat feature in Sublime Text 3 is Incremental Diff, which is very similar to the Git diff feature in VSCode, but it shows the diff since you first opened the file. It works for files that are not in a version-control system, and it's useful when quickly editing a file. I was wondering if something similar exists for VSCode. I love the diff provided by GitLens, but it's only limited to Git projects. I want to have it on every file I edit.