[in] Valid HINTERNET handle returned from a previous call to FtpOpenFile or an HINTERNET handle sent by HttpSendRequestEx.
[in] Pointer to a buffer that contains the data to be written to the file.
[in] Unsigned long integer value that contains the number of bytes to write to the file.
[out] Pointer to an unsigned long integer variable that receives the number of bytes written to the buffer.
Returns TRUE if the function succeeds, or FALSE otherwise.
This function is convenient when you want to store a local file on the FTP copying it as a series of relatively small pieces. In this case you can stop, suspend or abort the process and display its progress using the intervals between sending pieces.