@Override
    public String toString() {
        StringBuilder sb = new StringBuilder("Acknowledgements(");
        sb.append(acknowledgements);
        if (acknowledgeErrorCode != null) {
            sb.append(", errorCode=");
            sb.append(acknowledgeErrorCode.code());
        }
        sb.append(")");
        return sb.toString();
    }
@return Returns true if the array of acknowledge types in the share fetch batch contains a single acknowledge type
and the array size can be reduced to 1.
Returns false when the array has more than one acknowledge type or is already optimised.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/Acknowledgements.java