TODO: Expose tried IP addresses that failed

Suggested-by: Rainer Canavan

Closes #2126

docs/TODO

@@ -37,6 +37,7 @@
  1.21 API for URL parsing/splitting
  1.23 Offer API to flush the connection pool
  1.24 TCP Fast Open for windows
+ 1.25 Expose tried IP addresses that failed
 
  2. libcurl - multi interface
  2.1 More non-blocking
@@ -364,6 +365,13 @@
  Mac OS. Windows supports TCP Fast Open starting with Windows 10, version 1607
  and we should add support for it.
 
+1.25 Expose tried IP addresses that failed
+
+ When libcurl fails to connect to a host, it should be able to offer the
+ application the list of IP addresses that were used in the attempt.
+
+ https://github.com/curl/curl/issues/2126
+
 2. libcurl - multi interface
 
 2.1 More non-blocking