Hmmm, that doesn't seem to make sense to me.  That would mean that we can't use the `http-client` library for SSL unless we have a client certificate, right?  Not sure why a client certificate would have to be configured.  It wasn't necessary for the `clj-http` SSL connections to have a client certificate configured.  So long as a CA certificate is configured in the trust store, seems like we'd have enough for the client to trust the server.  Is this a deficiency in `http-kit`?