@VisibleForTesting(otherwise = VisibleForTesting.PROTECTED)
    final void createCustomAccessMessage(@NonNull final AccessMessage accessMessage) {
        final byte[] parameters = accessMessage.getParameters();
        final byte[] vendorOpcode = createVendorOpCode(accessMessage.getOpCode(),
                accessMessage.getCompanyIdentifier());
        final ByteBuffer accessMessageBuffer;
        if (parameters != null) {
            accessMessageBuffer = ByteBuffer.allocate(vendorOpcode.length + parameters.length);
            accessMessageBuffer.put(vendorOpcode);
            accessMessageBuffer.put(parameters);
        } else {
            accessMessageBuffer = ByteBuffer.allocate(vendorOpcode.length);
            accessMessageBuffer.put(vendorOpcode);
        }
        final byte[] accessPdu = accessMessageBuffer.array();
        MeshLogger.verbose(TAG, "Created Access PDU " + bytesToHex(accessPdu, false));
        accessMessage.setAccessPdu(accessPdu);
    }
Creates an access message

@param accessMessage Access message containing the required opcodes and parameters to create access message pdu.
mesh/src/main/java/no/nordicsemi/android/mesh/transport/AccessLayer.java