static int http_curl_progress_callback(void *, double, double, double, double);
static int http_curl_debug_callback(CURL *, curl_infotype, char *, size_t, void *);
static int http_curl_progress_callback(void *, double, double, double, double);
static int http_curl_debug_callback(CURL *, curl_infotype, char *, size_t, void *);