engine.start() does not work properly on AWS Lambda

[rhlsthrm]

I am trying to deploy an endpoint on AWS Lambda that implements a web3 provider engine. I am trying to use a private key to sign transactions with Web3 and INFURA. Here is some of my code (private data redacted):

module.exports.handler = (event, context, callback) => { // lambda boilerplate
  // get wallet from private key
  const myWallet = Wallet.fromV3(
    JSON.stringify({
      address: '<ADDRESS>',
      crypto: {
        // crypto params
    }),
    '<PASSWORD>',
    true
  )
  // console.log(web3)
  const providerUrl = 'https://kovan.infura.io/<INFURA_TOKEN>'
  const engine = new ProviderEngine()
  engine.addProvider(new WalletSubprovider(myWallet, {}))
  engine.addProvider(
    new Web3Subprovider(new Web3.providers.HttpProvider(providerUrl))
  )
  let web3 = new Web3(engine)
  engine.start()
  web3.eth.getBlockNumber((err, result) => {
    callback(
      null,
      success({
        message: 'Web3 is connected!',
        block: result
      })
    )
  })

Everything works fine when I run locally, but when I try to run it on AWS Lambda, I get timeout errors. I have pinpointed the issue to engine.start(). Is there a dependency with engine.start() on a specific Node version (Lambda runs 6.10)? Is there some sort of websocket or connection being opened that is not supported by Lambda?

[kumavis]

@rhlsthrm at some point we changed the default provider to fetch, maybe that was the issue. It was replaced with a polyfill.
additionally engine.start() now takes a callback that will catch the error.

Let me know if the latest version does not work on aws lambdas