OnePointMeter and TwoPointMeter, respectively, are base classes for meters
that measure on one port, or between two ports.
Within those base classes, a further distinction between meters that can be
attached to only one port or to more than one port is made in the base
classes OnePortXXXPointMeter, MultiPortXXXPointMeter.
CreateMessageFilter can be overridden to attach different filters to ports.
Fields inherited from class ikr.simlib.meters.Meter