Catch errors in metrics

I notice that api errors are not counted as errors in Cloudwatch metrics. I tested it also in Epsagon and it shows success even for functions that throw.

I've tried to get an error with the following code, they all return the correct HTTP code and message, but metrics does not catch them.
I have no middleware for errors.

module.exports.handler = async (event, context, callback) => {
  context.callbackWaitsForEmptyEventLoop = false;
  return await api.run(event, context, callback);
};

api.get('/profile/unauthorized', async (req, res) => {
  return res.error(401, 'unauthorized');
});

api.get('/profile/error', async (req, res) => {
  throw new Error('any error');
});

api.get('/profile/error500', async (req, res) => {
  return res.error(500, 'explicit error 500');
});

Start at the handler and api.run flow shown in the issue, then trace how thrown errors and res.error responses are represented for CloudWatch metrics and Epsagon. Reproduce the three profile routes and verify that unauthorized, explicit 500, and thrown errors are recorded as failures rather than successes.