developer guide: development note for Middleware Engineering

• why need Middleware Engineering
• how to do it

Middleware Engineering 🔥, like multi-version Java full support(support low version Java and full functions of high version Java), is boring but essential for middleware! 🤣

https://github.com/alibaba/transmittable-thread-local/releases/tag/v2.5.0

http://man7.org/linux/man-pages/man3/malloc_trim.3.html

This is a GNU extension, but it seems a lot of other allocators support it as well. It would be useful to have in e.g. system wide low-memory conditions.

I know you guys are focused on bringing more features to the lib, but it would be good to provide a bit better documentation and examples (I sent another post about this), so the ones willing to use the current version can fully understand what they can do with it..

E.g.

• I am not sure how to use signals, I can see raft::fileread uses raft::eof, but not sure what is done with it.
• I don't

Crash java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.RuntimeException: Unable to load script from assets 'threads/pre-load-data-worker.thread.bundle'. Make sure your bundle is packaged correctly or you're running a packager server.

![screen shot 2018-07-28 at 11 29 18](https://user-images.githubusercontent.com/3612098/43357535-8379af28-9259-11e8-9c5a-96