* Fired when the output hosting webview posts a message.
*/
readonlyonDidReceiveMessage:Event<any>;
/**
* Post a message to the output hosting webview.
*
* Messages are only delivered if the editor is live.
*
* @param message Body of the message. This must be a string or other json serilizable object.
*/
postMessage(message:any):Thenable<boolean>;
/**
* Create a notebook cell. The cell is not inserted into current document when created. Extensions should insert the cell into the document by [TextDocument.cells](#TextDocument.cells)