The starting message ID for the next query. If the number of messages returned by the SDK is smaller than the requested number, the cursor will be undefined.
isLast
isLast:boolean
Whether it is the last page of data.
true: Yes;
false: No.
If the number of data entries is smaller than the message count set in the request, false is returned; otherwise, true is returned.
The starting message ID for the next query. If the number of messages returned by the SDK is smaller than the requested number, the cursor will be
undefined.