src/vs/workbench/api/browser/mainThreadDocumentsAndEditors.ts/MainThreadDocumentsAndEditors/getIdOfCodeEditor
class MainThreadDocumentsAndEditors:	getIdOfCodeEditor(codeEditor: ICodeEditor): string | undefined {
		for (const [id, editor] of this._textEditors) {
			if (editor.getCodeEditor() === codeEditor) {
				return id;
			}
		}
		return undefined;
	}