anchor.diff:  
       ?assertMatch({error, _}, hlc:update(C, ?ts(SkewedTime, 0))),
   
  -    hlc:set_maxdrift(C, 0),
  +    hlc:set_maxoffset(C, 0),
       ?assertMatch(#timestamp{wall_time=SkewedTime},
                    hlc:update(C, ?ts(SkewedTime, 0))).
   
  
positive.code:     ?assertMatch(false, hlc:ts_equal(A, B1)).
  
  clock_test() ->
      {MClock, MClockFun} = hlc:manual_clock(),
      {ok, C} = hlc:new(MClockFun),
      hlc:set_maxdrift(C, 1000),
  
      Cases = [{5, send, nil, ?ts(5,0)},
               {6, send, nil, ?ts(6,0)},
  
negative.code:     {reply, NewTS, Clock#clock{ts=NewTS}};
  
  handle_call({update, RT}, _From, #clock{physical_clock=PhysicalCLock,
                                          ts=TS, maxoffset=MaxOffset}=Clock)  ->
      Now = PhysicalCLock(),
  
      #timestamp{wall_time=RTWalltime, logical=RTLogical} = RT,
  