Use executeBlocking to execute blocking method asynchronously

[Arooba-git]

Hi! :)
Apparently the code inside deployVerticle callback is blocking.. This PR fixes the blocking calls to keep the pipeline reactive.

Performance (latency) before fix

Performance after fix

[vietj]

can you sign the eclipse contributor agreement ?

[Arooba-git]

@vietj Hello!
As you can see in the screenshot, I already have :)

[tsegismont]

I fail to see how the screenshots (annotations on main thread state) relate to the updated test code (callback executed on an event loop thread).

This portion of test code looks harmless so I'm closing the issue.

[Arooba-git]

@tsegismont Hello!
The snapshots show that before the fix (with the blocking code), the main thread is being wasted just waiting or in parking state. After the fix, we can see the waiting/parking time reduced and the main thread being utilized usefully (green) :)

[tsegismont]

Hi @Arooba-git

I can see there is a difference between the two screenshots for the main thread. But it is not related to the changed code because it runs on an event loop thread.