private static long computeRecordSize(final Bytes key, final BufferValue value) {
        long size = 0L;
        size += 8; // buffer time
        size += key.get().length;
        if (value != null) {
            size += value.residentMemorySizeEstimate();
        }
        return size;
    }
As of 2.1, there's no way for users to directly interact with the buffer,
so this method is implemented solely to be called by Streams (which
it will do based on the {@code cache.max.bytes.buffering} config.
<p>
It's currently a no-op.
streams/src/main/java/org/apache/kafka/streams/state/internals/InMemoryTimeOrderedKeyValueChangeBuffer.java