anchor.diff:  %% + `State'
   %%     The probe state, originally returned by `probe_init/3' and subsequentially
   %%     modified by other probe implementation calls.
  -%% 
  -%% 
  +%%
  +%%
   %% The `probe_reset/1' implementation is invoked by
   %% `exometer:reset/1', which calls `exometer_probe:reset/3', which
   %% invokes the probe implementation.
  -%% 
  +%%
   %% The implementation of `probe_reset/1' shall return `{ok,
   %% NewState}', where `NewState' contains the reset state of the probe.
   %%
   %%
   %% === probe_sample/1 ===
   %% The `probe_sample/1' function is invoked as follows:
  -%% 
  +%%
   %% <pre lang="erlang">
   %%      probe_sample(State)</pre>
  -%% 
  +%%
   %% The `probe_sample/1' implementation shall sample data from the
   %% subsystem the probe is integrated with.
   %%
  
positive.code: %%
  %% + `DataPoints'
  %%     List of data point atoms to retrieve values for.
  %% 
  %% + `State'
  %%     The probe state, originally returned by `probe_init/3' and subsequentially
  %%     modified by other probe implementation calls.
  %% 
  %% The `probe_get_value/2' implementation is invoked by
  %% `exometer:get_value/2', which calls `exometer_probe:get_value/4',
  %% which invokes the probe implementation.
  %% 
  %% If `exometer:get_value/2' is invoked with `default' as a single
  %% data point, the probe's `probe_get_datapoints/1' function will be
  %% called to retrieve all data points supported by the probe
  
negative.code: %% Once processed, `probe_update/2' shall return `{ok, NewState}',
  %% where `NewState' contains the new probe state with the processed
  %% value.
  %%
  %%
  %% === probe_get_value/2 ===
  %% The `probe_get_value/2' function is invoked as follows:
  %%
  %% <pre lang="erlang">
  %%      probe_get_value(DataPoints, State)</pre>
  %%
  %% The `probe_get_value/2' implementation shall retrieve the value of
  %% one or more data points from the probe.
  %%
  