The problem happens for bidirectional flows. The sequence of events is
as follows when you start Tx on Ports p1, p2 with the current code -
1. Clear stream stats on p1
2. Start tx on p1
3. Clear stream stats on p2
4. Start tx on p2
By the time #3 is executed, it may have already rx packets from p1 which
are being incorrectly cleared, this will cause these number of packets
to show up as dropped instead - incorrectly.
The fix is to change the order like this -
1. Clear stream stats on p1
2. Clear stream stats on p2
3. Start tx on p1
4. Start tx on p2
Unidirectional flows will not see this problem - as long as startTx is
done only on the Tx port and not the Rx port.
This bug is a regression caused due to the code changes introduced for the
stream stats rates feature implemented in 1.2.0
