Merge "Use raw transport if Android T or below" into udc-dev

        int sdk = Build.VERSION.SDK_INT;

        String release = Build.VERSION.RELEASE;

        if (Build.isDebuggable()) {

            // Debug builds cannot pass attestation verification. Use hardcoded key instead.

        if (sdk < SECURE_CHANNEL_AVAILABLE_SDK || remoteSdk < SECURE_CHANNEL_AVAILABLE_SDK) {

            // If either device is Android T or below, use raw channel

            // TODO: depending on the release version, either

            //       1) using a RawTransport for old T versions

            //       2) or an Ukey2 handshaked transport for UKey2 backported T versions

            Slog.d(TAG, "Secure channel is not supported. Using raw transport");

            transport = new RawTransport(transport.getAssociationId(), transport.getFd(), mContext);

        } else if (Build.isDebuggable()) {

            // If device is debug build, use hardcoded test key for authentication

            Slog.d(TAG, "Creating an unauthenticated secure channel");

            final byte[] testKey = "CDM".getBytes(StandardCharsets.UTF_8);

            transport = new SecureTransport(transport.getAssociationId(), transport.getFd(),

                    mContext, testKey, null);

        } else if (remoteSdk == NON_ANDROID) {

        } else if (sdk == NON_ANDROID || remoteSdk == NON_ANDROID) {

            // If either device is not Android, then use app-specific pre-shared key

            // TODO: pass in a real preSharedKey

            Slog.d(TAG, "Creating a PSK-authenticated secure channel");

            transport = new SecureTransport(transport.getAssociationId(), transport.getFd(),

                    mContext, new byte[0], null);

        } else if (sdk >= SECURE_CHANNEL_AVAILABLE_SDK

                && remoteSdk >= SECURE_CHANNEL_AVAILABLE_SDK) {

            Slog.i(TAG, "Creating a secure channel");

        } else {

            // If none of the above applies, then use secure channel with attestation verification

            Slog.d(TAG, "Creating a secure channel");

            transport = new SecureTransport(transport.getAssociationId(), transport.getFd(),

                    mContext);

        } else {

            // TODO: depending on the release version, either

            //       1) using a RawTransport for old T versions

            //       2) or an Ukey2 handshaked transport for UKey2 backported T versions

        }

        addMessageListenersToTransport(transport);

        transport.start();