return the packet ID, which is a number from 1-99.
return the list of planes in an unmodifiable list.
If true, then slices of the dataset fill each packet.
keep track of the packet ID, which is a number from 1-99.
number of dimensions being streamed. Zero means all the data is found in the first packet (no streaming). One means a qube is being streamed. Two means a this packet is one qube of a higher rank dataset.