https://github.com/apache/spark/blob/v1.0.0/core/src/main/scala/org/apache/spark/serializer/Serializer.scala#L64-L66
These changes to the SerializerInstance make it really gross to call serialize and deserialize from non-scala languages. I'm not sure what the purpose of a ClassTag is, but if we could get some other arities that don't require classtags that would help a ton.
