1.15 TCP Fast Open
1.16 Try to URL encode given URL
1.17 Add support for IRIs
+ 1.18 try next proxy if one doesn't work
2. libcurl - multi interface
2.1 More non-blocking
To make that work smoothly for curl users even on Windows, curl would
probably need to be able to convert from several input encodings.
+1.18 try next proxy if one doesn't work
+
+ Allow an application to specify a list of proxies to try, and failing to
+ connect to the first go on and try the next instead until the list is
+ exhausted. Browsers support this feature at least when they specify proxies
+ using PACs.
+
+ https://github.com/curl/curl/issues/896
+
2. libcurl - multi interface