ISAPI filters receive this notification immediately prior to sending the headers to the client. The filter can inspect, modify, or add headers the client will receive as part of the response to the client's original request The structure contains the same members as HTTP_FILTER_PREPROC_HEADERS. When a filter has registered for the SF_NOTIFY_SEND_RESPONSE event, the pvNotification parameter of HttpFilterProc will point to this structure.
typedef struct HTTP_FILTER_SEND_RESPONSE;
{
BOOL (WINAPI * GetHeader) ;
BOOL (WINAPI * SetHeader) ;
BOOL (WINAPI * AddHeader) ;
DWORD HttpStatus;
DWORD dwReserved;
} HTTP_FILTER_SEND_RESPONSE, *PHTTP_FILTER_SEND_RESPONSE;