chore: use es6 arrows function

[SimonSchick]

This converts most function callback use to arrow functions.

I will push 3 invidual commits and run them through CI (builds are extremely flaky locally).
The first 2 will run CI without lint, the 3rd one adds linting back.

The first commit was entirely automated via eslint.
The second and 2nd is fixing docs and invalid-this errors.
The 3rd final invalid-this errors.

[sidorares]

Interesting to see if there is perf impact of this change ( could be either way )

[SimonSchick]

Doubtful, especially given https://stackoverflow.com/questions/44030645/are-arrow-functions-faster-more-performant-lighter-than-ordinary-standalone-f

It mostly helps with code readability as they are less verbose and don't change this all the time.

On another note: I changed the way the db awaiter works, less spam :)
https://github.com/sidorares/node-mysql2/pull/870/files#diff-8736c5cbff21e1dee18b0c86d3d2689dR32

[sidorares]

On another note: I changed the way the db awaiter works, less spam :)

Thanks! One more thing to improve with test signal/noise ratio is to clean up "packet out of order" messages from test server (or actually fix packet numbers in server)

[SimonSchick]

Yea, that's out of scope of my PR tho, plus I'm not exactly sure how I would fix those 😛

[SimonSchick]

rebased

[SimonSchick]

Broke link, goddamnit 😞

[SimonSchick]

Hey @sidorares would you like to merge this and resolve conflicts yourself, or should I rebase again?

[sidorares]

if you can would be great, otherwise I'll do

[SimonSchick]

Done, hoping that tests pass :)

[SimonSchick]

Oh great, I amended without pulling first 😅

[SimonSchick]

@sidorares I think this is ripe now, I checked for additional arguments magic just to be sure.