@InterfaceStability.Evolving
public interface WriterCommitMessage
extends java.io.Serializable
DataWriter.commit() and will be sent back to the driver side
as the input parameter of DataSourceWriter.commit(WriterCommitMessage[]).
This is an empty interface, data sources should define their own message class and use it in
their DataWriter.commit() and DataSourceWriter.commit(WriterCommitMessage[])
implementations.