Call this method to retrieve a copy of the last HTTP response headers received.
A pointer to a buffer that is to receive the response header data. If 0, the size of the response headers is returned by the pdwLen argument, and the header data is not retrieved.
The size of the buffer.
The size specified by pdwLen must be sufficient for storage of the response header data. The required size can be determined either by using the GetRawResponseHeaderLength method or by passing 0 for the szBuffer argument.