#### Summary

It looks like latest version includes `buffer.js` on the browser bundle even if not actually used.
This makes axios bundle size **3 times bigger**, adding 22kB to the minified size (0.16.0 is 11.9 KB while 0.16.1 is 33.9kB).

#### Context

- axios version: v0.16.1

lib/adapters/http.js
if (!headers['User-Agent'] && !headers['user-agent']) {
      headers['User-Agent'] = 'axios/' + pkg.version;
    }
    if (data && !utils.isStream(data)) {
      if (utils.isBuffer(data)) {
        
      } else if (utils.isArrayBuffer(data)) {
        data = new Buffer(new Uint8Array(data));
      } else if (utils.isString(data)) {
        data = new Buffer(data, 'utf-8');
      } else {
        return reject(createError(
          'Data after transformation must be a string, an ArrayBuffer, a Buffer, or a Stream',
          config
        ));
      }
      
      headers['Content-Length'] = data.length;
    }
    
    var auth = undefined;
    if (config.auth) {
      var username = config.auth.username || '';
      var password = config.auth.password || '';
      auth = username + ':' + password;
    }