docs: function summary (server, write) {
    assert.ok(server instanceof http.Server, /expected instance of server/)
    write = write || defaultWrite
  
    return function () {
      const address = server.address()
      const port = address.port
      const url = 'http://localhost:' + port
      const env = process.env.NODE_ENV || 'undefined'
  
      write({
        port: port,
        env: env,
        pid: process.pid,
        url: url
      })
    }
  }