src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts/BackLayerWebView/postKernelMessage
class BackLayerWebView:	postKernelMessage(message: any) {
		this._sendMessageToWebview({
			__vscode_notebook_message: true,
			type: 'customKernelMessage',
			message,
		});
	}