SSL + libcurl: connection seems dead

[igorgatis]

There seems to exist a bad interaction between libcurl and Nowin with SSL/TLS persistent connections.

curl -v -3 https://somenowinserver.com/robots.txt https://somenowinserver.com/robots.txt https://somenowinserver.com/robots.txt 2>&1 | grep -i connection
* SSL connection using SSLv3 / DES-CBC3-SHA
* Connection #0 to host somenowinserver.com left intact
* Re-using existing connection! (#0) with host somenowinserver.com
* Connection #0 to host somenowinserver.com left intact
* Connection 0 seems to be dead!
* Closing connection 0
* SSL connection using SSLv3 / DES-CBC3-SHA
* Connection #1 to host somenowinserver.com left intact

The 2nd GET resumes SSL session (Re-using existing connection) but the 3rd doesn't (Connection 0 seems to be dead!)

I was able to reproduce the problem both with Windows client and Linux (Ubuntu) client. I noticed this problem with Nowin version 0.16.0.0 but 0.22.2.0 also behaves in the same way.