make JSON output logging less noisy

[michiboo]

Address issues #1469
Increase time interval between log message to 200 milliseconds
Remove Writing JSON metrics message
Add if statement output log based on no of count

[CLAassistant]

All committers have signed the CLA.

[na--]

Thanks for making this PR! Not sure if you've seen the lint error, but please move the 200ms to a constant so that is stops complaining 😅

[na--]

Thanks, LGTM! I have no idea why the linter fails, it's supposed to ignore old linter issues that PRs haven't touched 😕

[imiric]

The linter is probably getting confused since this branch seems to have been based on an old master commit, and the PR is to new-schedulers.

@michiboo Can you rebase your reduce_verbose branch on the current new-schedulers (d932446)? EDIT: Nevermind, it was mergable as is, and the linter should pass on the new-schedulers build. Thanks for your contribution!