src/vs/workbench/contrib/codeEditor/browser/outline/documentSymbolsOutline.ts/DocumentSymbolsOutline/_setOutlineModel
class DocumentSymbolsOutline:	private _setOutlineModel(model: OutlineModel | undefined) {
		const position = this._editor.getPosition();
		if (!position || !model) {
			this._outlineModel = undefined;
			this._breadcrumbsDataSource.clear();
		} else {
			if (!this._outlineModel?.merge(model)) {
				this._outlineModel = model;
			}
			this._breadcrumbsDataSource.update(model, position);
		}
		this._onDidChange.fire({});
	}