anchor.diff:  -define(TRACE(X,Y), ok).
   -include("scalaris.hrl").
   -include("record_helpers.hrl").
  +
  +-define(WARN(BOOL, BOOL2, TEXT), 
  +        if
  +            BOOL andalso not (BOOL2) ->
  +                log:log("loncq: " ++ TEXT);
  +            true -> ok
  +        end).
   
   -export([read/1, read/2]).
   %%-export([write/2]).
  
positive.code: 
  -spec is_valid(lease_t()) -> boolean().
  is_valid(L) ->
      os:timestamp() <  L#lease.timeout.
  
  -spec has_timed_out(lease_t()) -> boolean().
  has_timed_out(L) ->
  
negative.code: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  % @doc generic content check. used for almost all qwrite operations
  -spec generic_content_check_(lease_t(), lease_t(), atom()) -> 
                                     content_check_t(). %% content check
  generic_content_check_(#lease{id=OldId,owner=_OldOwner,aux = OldAux,range=OldRange,
                               epoch=OldEpoch,version=OldVersion,timeout=OldTimeout} = Old,
                       New, Writer) ->
      fun(prbr_bottom, _WriteFilter, Next) ->
              {false, {lease_does_not_exist, pbr_bottom, Next}};
          (Current, _WriteFilter, Next) when Current =:= New ->
              log:pal("re-write in CC:~n~w~n~w~n~w~n~w~n~w~n", [Current, Next, Old, New, Writer]),
              {true, null};
          (#lease{id = Id0} = Current, _, Next)    when Id0 =/= OldId->
              {false, {unexpected_id, Current, Next}};
          %(#lease{owner = O0} = Current, _, Next)    when O0 =/= OldOwner->
          %    {false, {unexpected_owner, Current, Next}};
          (#lease{aux = Aux0} = Current, _, Next)    when Aux0 =/= OldAux->
              {false, {unexpected_aux, Current, Next}};
          (#lease{range = R0} = Current, _, Next)    when R0 =/= OldRange->
  