src/vs/workbench/contrib/bulkEdit/browser/preview/bulkEditPreview.ts/BulkEditPreviewProvider/_applyTextEditsToPreviewModel
class BulkEditPreviewProvider:	private async _applyTextEditsToPreviewModel(uri: URI) {
		const model = await this._getOrCreatePreviewModel(uri);

		// undo edits that have been done before
		const undoEdits = this._modelPreviewEdits.get(model.id);
		if (undoEdits) {
			model.applyEdits(undoEdits);
		}
		// apply new edits and keep (future) undo edits
		const newEdits = this._operations.getFileEdits(uri);
		const newUndoEdits = model.applyEdits(newEdits, true);
		this._modelPreviewEdits.set(model.id, newUndoEdits);
	}