Describe the bug
In our application we noticed a significant performance overhead from using the default async_hooks-based scope manager. After adding scope: 'noop' to our config, we saw the following improvements.

CPU usage halved:

Significantly smaller GC pauses, with less variance:

After researching this further, we found that use of async_hooks is known to cause significant performance degradation:

• Performance impact of async_hooks nodejs/benchmarking#181
• https://blog.jakubholy.net/2018/11/01/beware-the-performance-cost-of-async_hooks-node-8/

Are there any official recommendations for configuring the node environment and/or dd-trace-js to reduce the overhead of DataDog's async_hooks usage? Is using scope: 'noop' a viable approach? What effects would this have on plugins?

Environment

• Operation system: Debian
• Node version: 10.16.3
• Tracer version: 0.15.2
• Agent version: 6.13.0