src/vs/workbench/services/textfile/browser/textFileService.ts/AbstractTextFileService/isDirty
class AbstractTextFileService:	isDirty(resource: URI): boolean {
		const model = resource.scheme === Schemas.untitled ? this.untitled.get(resource) : this.files.get(resource);
		if (model) {
			return model.isDirty();
		}

		return false;
	}