static int url_seek_packet(void *opaque, int64_t offset, int whence)
static offset_t url_seek_packet(void *opaque, offset_t offset, int whence)
static int url_seek_packet(void *opaque, int64_t offset, int whence){    URLContext *h = opaque;    return url_seek(h, offset, whence);    //return 0;}