anchor.diff:  
   -spec to_texfile(trace(), file:name()) -> ok | {error, file:posix() | badarg | terminated}.
   to_texfile(Trace, Filename) ->
  +    to_texfile(Trace, Filename, fun time_delta/1, true).
  +
  +-spec to_texfile_no_time(trace(), file:name()) -> ok | {error, file:posix() | badarg | terminated}.
  +to_texfile_no_time(Trace, Filename) ->
  +    to_texfile(Trace, Filename, fun notime_delta/1, false).
  +
  +-spec to_texfile(trace(), file:name(), DeltaFun::fun((trace()) -> trace()),
  +                 HaveRealTime::boolean())
  +        -> ok | {error, file:posix() | badarg | terminated}.
  +to_texfile(Trace, Filename, DeltaFun, HaveRealTime) ->
       ScaleX = 20, %% 1 cm is ScaleX microseconds in the plot
       TicsFreq = 20, %% draw x-tics every TicsFreq microseconds
   
  
positive.code:               "  \\draw[color=red!50!black,->] (-2cm, 0.5)"
                "  -- (-1.5cm, 0.5) node[anchor=west] {global send};~n", []),
  
      draw_messages(File, Nodes, ScaleX, DrawTrace),
  
      io:format(
        File,
  
negative.code: %% trace analysis
  -export([send_histogram/1]).
  -export([time_delta/1]).
  -export([to_texfile/2, to_texfile_no_time/2]).
  
  %% report tracing events from other modules
  -export([log_send/5]).
  