uploaded bytes with the normal read function/callback). It is also called to
rewind a stream when doing a HTTP PUT or POST with a multi-pass authentication
method. The function shall work like "fseek" or "lseek" and accepted SEEK_SET,
-SEEK_CUR and SEEK_END as argument for origin, although (in 7.18.0) libcurl
-only passes SEEK_SET. The callback must return 0 (CURL_SEEKFUNC_OK) on
-success, 1 (CURL_SEEKFUNC_FAIL) to cause the upload operation to fail or 2
+SEEK_CUR and SEEK_END as argument for origin, although libcurl currently only
+passes SEEK_SET. The callback must return 0 (CURL_SEEKFUNC_OK) on success, 1
+(CURL_SEEKFUNC_FAIL) to cause the upload operation to fail or 2
(CURL_SEEKFUNC_CANTSEEK) to indicate that while the seek failed, libcurl is
free to work around the problem if possible. The latter can sometimes be done
by instead reading from the input or similar.