src/vs/workbench/api/common/extHostNotebookKernels.ts/ExtHostNotebookKernels/$cellExecutionChanged
class ExtHostNotebookKernels:	$cellExecutionChanged(uri: UriComponents, cellHandle: number, state: NotebookCellExecutionState | undefined): void {
		const document = this._extHostNotebook.getNotebookDocument(URI.revive(uri));
		const cell = document.getCell(cellHandle);
		if (cell) {
			const newState = state ? extHostTypeConverters.NotebookCellExecutionState.to(state) : ExtHostNotebookCellExecutionState.Idle;
			if (newState !== undefined) {
				this._onDidChangeCellExecutionState.fire({
					cell: cell.apiCell,
					state: newState
				});
			}
		}
	}