typedef TPostingDataEvent TPostingDataEvent;
TPostingDataEvent is the type of the OnPostingData event of THTTPReqResp.
TPostingDataEvent is the type of the OnPostingData event handler, which is called after each chunk of data that is sent when a request is very large.
Sent indicates the (cumulative) number of bytes that have already been sent.
Total indicates the total number of bytes that need to be sent.