fun SSLSession.handshake(): Handshake {
      val cipherSuite =
        when (val cipherSuiteString = checkNotNull(cipherSuite) { "cipherSuite == null" }) {
          "TLS_NULL_WITH_NULL_NULL", "SSL_NULL_WITH_NULL_NULL" -> {
            throw IOException("cipherSuite == $cipherSuiteString")
          }

          else -> {
            CipherSuite.forJavaName(cipherSuiteString)
          }
        }