TODO: Separate bidiStreamCount and uniStreamCount properties #314

Currently, QuicStream has separate bidiStreamCount and uniStreamCount properties that return the total number of streams of each type. The question is whether these are good as separate properties or whether it would be more useful to combine into a single property that returns both, as in:

const {uni, bidi} = session.streamCount;

Note: there are lots of other statistics properties on the QuicSession