code: function(error, content) {
  
            var isInitializing = (callback !== null),
                initCallback = callback;
            callback = null;
  
            if (error && error.code === 'ENOENT') {
              // File doesn't exist. Set the model to null.
              t.set({model: {}}, {silent: isInitializing});
              // Convert the code from the sync probe spec
              error.code = 'NOTFOUND';
            }
            if (error) {
              if (isInitializing) {
                t.release();
                var err = {code: error.code, msg: 'LiveSync requires the file to exist and be readable'};
                initCallback(err);
              }
              return;
            }
  
            // Parse the JSON content into a JS object.
            try {
              content = JSON.parse(content);
              logger.info('fileParse', {id: t.get('modelId'), content: content});
            } catch (e) {
  
              // Fail the probe on first load error
              if (isInitializing) {
                t.release();
                initCallback({code: 'BAD_FORMAT', msg: 'Non-JSON formatted file'});
              }
  
              // Nothing productive to do if the file can't be parsed. Just log it.
              logger.error('fileParse', {error: e, id: t.get('modelId'), content: content});
              return;
            }
  
            // Set the content into the model if it's different
            // Have to compare raw objects because toJSON returns deep references to models
            var priorModel = t.get('model');
            if (!priorModel || !_.isEqual(content, JSON.parse(JSON.stringify(priorModel)))) {
              t.set({model: content}, {silent: isInitializing});
            }
  
            // Call the initialization callback on first load
            if (isInitializing) {
              initCallback();
            }
          }
docs: Build the function to watch the file