code: function(datasetClientId, fieldsToUpdate, callback) {
        return metrics.timeAsyncFunc(metrics.KEYS.MONGODB_OPERATION_TIME, doUpdateDatasetClient)(datasetClientId, fieldsToUpdate, false, callback);
      }
docs: update the given dataset client
  @param {String} datasetClientId the id of the datasetClient
  @param {storage~DatasetClient} fieldsToUpdate the fields to update
  @param {Function} callback