Twapi is helpful to be used for https on Windows instead the TLS package for update reasons (twapi gets updated with the operating system, with TLS (on windows), the program author must care to update openssl if required).

For instance, it does not work with autoproxy.
Wiki page for some details:

It is examined in TWAPI and here, to find out:
   *   if this is possible
   *   what must be changed in twapi and autoproxy

Here is the twapi ticket: