src/vs/workbench/api/common/extHostNotebookEditors.ts/NotebookEditorDecorationType/constructor
class NotebookEditorDecorationType:	constructor(proxy: MainThreadNotebookEditorsShape, options: vscode.NotebookDecorationRenderOptions) {
		const key = NotebookEditorDecorationType._Keys.nextId();
		proxy.$registerNotebookEditorDecorationType(key, typeConverters.NotebookDecorationRenderOptions.from(options));

		this.value = {
			key,
			dispose() {
				proxy.$removeNotebookEditorDecorationType(key);
			}
		};
	}