require an installed node module about npool

[inh3]

This is actually not a bug. Unfortunately, built-in or native add-on node modules are not accessible in background threads because they are dependent on the main thread's libuv run loop. Also, they rely upon much of the native code of node itself.

The guidelines for using require(...) in background threads are as follows:

• Modules and their dependencies must be pure javascript
• Utilize a relative or full path for each require(...) statement (including the file extension)
• setInterval, clearInterval, setTimeout, and clearTimeout are not available

https://github.com/inh3/nPool#thread-module-support