src/vs/workbench/common/editor/diffEditorInput.ts/DiffEditorInput/createModel
class DiffEditorInput:	private async createModel(): Promise<DiffEditorModel> {

		// Join resolve call over two inputs and build diff editor model
		const [originalEditorModel, modifiedEditorModel] = await Promise.all([
			this.original.resolve(),
			this.modified.resolve()
		]);

		// If both are text models, return textdiffeditor model
		if (modifiedEditorModel instanceof BaseTextEditorModel && originalEditorModel instanceof BaseTextEditorModel) {
			return new TextDiffEditorModel(originalEditorModel, modifiedEditorModel);
		}

		// Otherwise return normal diff model
		return new DiffEditorModel(withNullAsUndefined(originalEditorModel), withNullAsUndefined(modifiedEditorModel));
	}