read-only ByteBuffer not supported

[praetp]

I was trying to write a read-only ByteBuffer to DynamoDb using the connector but I got

Caused by: java.nio.ReadOnlyBufferException
	at java.nio.ByteBuffer.array(ByteBuffer.java:996)
	at org.apache.hadoop.dynamodb.DynamoDBUtil.getAttributeSizeBytes(DynamoDBUtil.java:176)
	at org.apache.hadoop.dynamodb.DynamoDBUtil.getItemSizeBytes(DynamoDBUtil.java:149)
	at org.apache.hadoop.dynamodb.DynamoDBClient.putBatch(DynamoDBClient.java:199)
	at org.apache.hadoop.dynamodb.write.AbstractDynamoDBRecordWriter.write(AbstractDynamoDBRecordWriter.java:112)
	at org.apache.spark.internal.io.HadoopMapRedWriteConfigUtil.write(SparkHadoopWriter.scala:238)
	at org.apache.spark.internal.io.SparkHadoopWriter$$anonfun$4.apply(SparkHadoopWriter.scala:132)
	at org.apache.spark.internal.io.SparkHadoopWriter$$anonfun$4.apply(SparkHadoopWriter.scala:129)
	at org.apache.spark.util.Utils$.tryWithSafeFinallyAndFailureCallbacks(Utils.scala:1439)
	at org.apache.spark.internal.io.SparkHadoopWriter$.org$apache$spark$internal$io$SparkHadoopWriter$$executeTask(SparkHadoopWriter.scala:141)
	... 10 more

This is very unexpected as the API of AttributeValue().withB() clearly states:

Warning: ByteBuffers returned by the SDK are mutable. Changes to the content or position of the byte buffer will be seen by all objects that have a reference to this object. It is recommended to call ByteBuffer.duplicate() or ByteBuffer.asReadOnlyBuffer() before using or reading from the buffer. This behavior will be changed in a future major version of the SDK.

So the API docs are actually encouraging us to provided a ReadOnly buffer.