CallbackResolver and AWS Lambda

[H4ad]

Current Behavior

Almost all requests using CallbackResolver inside AWS Lambda are taking too long,
with PromiseResolver I didn't see this same delay.

Expected Behavior

To work as PromiseResolver works.

Steps to Reproduce the Problem

1. Use CallbackResolver on setResolver.
2. Deploy your app inside AWS Lambda.
3. Make some request.

Environment

• Version: 2.6.0
• Platform: Linux
• Node.js Version: 14.x