public void add(MessageSizeAccumulator size) {
        this.totalSize += size.totalSize;
        this.zeroCopySize += size.zeroCopySize;
    }
Size excluding zero copy fields as specified by {@link #zeroCopySize}. This is typically the size of the byte
buffer used to serialize messages.
clients/src/main/java/org/apache/kafka/common/protocol/MessageSizeAccumulator.java