private byte[] createUnsegmentedAccessMessage(@NonNull final AccessMessage message) {
        final byte[] encryptedUpperTransportPDU = message.getUpperTransportPdu();
        final int seg = message.isSegmented() ? 1 : 0;
        final int akfAid = ((message.getAkf() << 6) | message.getAid());
        final byte header = (byte) (((seg << 7) | akfAid));
        final ByteBuffer lowerTransportBuffer = ByteBuffer.allocate(1 + encryptedUpperTransportPDU.length).order(ByteOrder.BIG_ENDIAN);
        lowerTransportBuffer.put(header);
        lowerTransportBuffer.put(encryptedUpperTransportPDU);
        final byte[] lowerTransportPDU = lowerTransportBuffer.array();
        MeshLogger.verbose(TAG, "Unsegmented Lower transport access PDU " + MeshParserUtils.bytesToHex(lowerTransportPDU, false));
        return lowerTransportPDU;
    }
Creates an unsegmented access message.

@param message access message.
@return Unsegmented access message.
mesh/src/main/java/no/nordicsemi/android/mesh/transport/LowerTransportLayer.java