NFD

This is unnecessary because there is no cost in transmitting to and from an InternalFace.

We should add this for uniformity. The status page looks odd without these stats. This is number of bytes that correspond to Interest/Data the InternalFace has received or generated.

It's semantically incorrect to have link layer byte counts on InternalFace, because this type of face operates on application layer, and has no link layer.
Therefore, it's fine to keep the link layer counters at zero.

Perhaps, counters that are not applicable to a type of face should be omitted in FaceStatus block.