JavaScript: Buffer is not defined in browser environment

When I use avro in my browser, I find that I get the `Buffer is undefined error`

The code I use is simple, it comes from the github repository readme.md

var avro = require('avro-js');
var type = avro.parse({
  name: 'Pet',
  type: 'record',
  fields: [
    {name: 'kind', type: {name: 'Kind', type: 'enum', symbols: ['CAT', 'DOG']}},
    {name: 'name', type: 'string'}
  ]
});
var pet = {kind: 'CAT', name: 'Albert'};
var buf = type.toBuffer(pet); // Serialized object.
var obj = type.fromBuffer(buf); // {kind: 'CAT', name: 'Albert'}

Later I traced the source code and found that Buffer is used directly in `/etc/browser/avro.js` and `/lib/schema.js`, which is not a problem in the node environment because the Buffer object is mounted globally, but it is a problem in the browser environment because using buffer polyfill will not mount the Buffer object globally, You need to  declare `var Buffer = require('buffer').Buffer` manually, so that it can be used in the browser environment without affecting the node environment, which also gets its Buffer from require('buffer').