@Override
    public int getOpCode() {
        return mOpCode;
    }
Constructs VendorModelMessageAcked message.

@param appKey            {@link ApplicationKey} for this message
@param modelId           model identifier
@param companyIdentifier Company identifier of the vendor model
@throws IllegalArgumentException if any illegal arguments are passed
mesh/src/main/java/no/nordicsemi/android/mesh/transport/VendorModelMessageUnacked.java