Function handler

test/request-error.test.js:372–375

(req, res)

  t.plan(3)
  const fastify = Fastify()
  const handler = function (req, res) {
    t.assert.strictEqual('POST', req.routeOptions.method)
    res.send({})
  }

  fastify.post('/', {
    bodyLimit: 1000,