fix byteBuffer in spark3

Author: wangzixuan.wzxuan

hudi-spark-datasource/hudi-spark3.1.x/src/main/scala/org/apache/spark/sql/avro/AvroDeserializer.scala

@@ -167,6 +167,8 @@ private[sql] class AvroDeserializer(rootAvroType: Schema,
           case b: ByteBuffer =>
             val bytes = new Array[Byte](b.remaining)
             b.get(bytes)
+            // Do not forget to reset the position
+            b.rewind()
             bytes
           case b: Array[Byte] => b
           case other => throw new RuntimeException(s"$other is not a valid avro binary.")

hudi-spark-datasource/hudi-spark3/src/main/scala/org/apache/spark/sql/avro/AvroDeserializer.scala

@@ -181,6 +181,8 @@ private[sql] class AvroDeserializer(rootAvroType: Schema,
           case b: ByteBuffer =>
             val bytes = new Array[Byte](b.remaining)
             b.get(bytes)
+            // Do not forget to reset the position
+            b.rewind()
             bytes
           case b: Array[Byte] => b
           case other =>