anchor.diff:  %% + `State'
   %%     The probe state, originally returned by `probe_init/3' and subsequentially
   %%     modified by other probe implementation calls.
  -%% 
  +%%
   %% When invoked, `probe_sample/1' is expected to interface the
   %% sub-system (/proc, /sysfs, etc) monitored by the probe, extract the
   %% relevant data from it, and return an updated probe state that
  
positive.code: %%
  %% This function shall return the value of all data points provided in
  %% `DataPoints', given that they are supported.
  %% 
  %% The list in the returned tuple shall have the format:
  %%
  %% <pre lang="erlang">
  
negative.code: %%
  %% + `Opts'
  %%     The probe-specific options to be processed.
  %%
  %% + `State'
  %%     The probe state, originally returned by `probe_init/3' and subsequentially
  %%     modified by other probe implementation calls.
  %%
  %% This function shall return `{ok, NewState}' where `NewState' is
  %% the modified probe state that incorporates the new options.
  %%
  %%
  %% === probe_update/2 ===
  %% The `probe_update/2' function is invoked as follows:
  %%
  %% <pre lang="erlang">
  %%      probe_update(Value, State)</pre>
  %%
  %% Incorporate a new value into the metric maintained by the metric.
  %%
  %% The arguments are as follows:
  %%
  %% + `Value'
  %%     The value to integrate.
  %%
  %% + `State'
  %%     The probe state, originally returned by `probe_init/3' and subsequentially
  %%     modified by other probe implementation calls.
  %%
  %% This function can be called outside the periodic `probe_sample/1/'
  %% call to have the probe process a value given in `Value'.
  %%
  