T- tset type
public interface AcceptingData<T>
TSets to accept data from another TSet as an input. Only the Batch TSets can accept inputs.
This remains as a separate interface because SinkTSet behaves differently to all other BatchTSets. i.e. It does not expose any communication operations. But a SinkTSet needs to be able to accept data from another TSet. Therefore, that capability was separated out.