anchor.diff:      CallId. 
   
   
  +%% @doc Get specific metadata from the dialog
   -spec meta(field()|[field()], nksip:dialog()|nksip:id()) -> 
       term() | [{field(), term()}] | error.
   
  
positive.code: 
  
  %% @doc Finds all existing dialogs having a `Call-ID'.
  -spec get_all(nksip:app_id(), nksip:call_id()) ->
      [nksip:id()].
  
  get_all(App, CallId) ->
  
negative.code: 
  
  %% @doc Gets app's name
  -spec app_name(nksip:dialog()|nksip:id()) -> 
      term().
  
  app_name(Dialog) -> 
      (app_id(Dialog)):name().
  
  
  %% @doc Gets thel Call-ID of a dialog
  