Implement tracking orphaned stream ids

[psarna]

If a server never responds for a given stream id, we might run out of all ids, which makes the connection defunct. We should track the number of ids that got orphaned - i.e. client-side timeout was already fired for a request, but we didn't get a response from it yet, so we can't release the stream id. Once we hit a threshold for orphaned ids, the connection should be closed and reinstantiated.