+NOTES
+ Block I/O statistics
+ This I/O value is the amount of I/O since the previous iteration of
+ virt-top. To calculate speed of I/O, you should divide the number by
+ delay secs.
+
+ NETWORK RX BYTES AND PACKETS
+ Libvirt/virt-top has no way to know that a packet transmitted to a guest
+ was received (eg. if the guest is not listening). In the network RX
+ stats, virt-top reports the packets transmitted to the guest, on the
+ basis that the guest might receive them.
+
+ In particular this includes broadcast packets. Because of the way that
+ Linux bridges work, if the guest is connected to a bridge, it will
+ probably see a steady "background noise" of RX packets even when the
+ network interface is idle or down. These are caused by STP packets
+ generated by the bridge.
+