Support reuse current eventLoop for Deployment

[dreamlike-ocean]

add new ThreadingModel to support reuse current eventLoop for deploying verticle

Motivation:

Sometimes we expect to deploy child verticles using the current EventLoop. This can ensure the affinity between multiple child verticles and the parent verticle.

Moreover, when deploying a large number of verticles, if the current EventLoop cannot be reused, it will generate a large amount of system call overhead caused by selector::wakeup.

directly deploy verticle:

reuse eventLoop for deploying verticle

So I provided a new ThreadingModel enum and made some compatibility. When creating an eventLoopContext, the EventLoop corresponding to the current Context will be used as the EventLoop of the new eventLoopContext.

Conformance:
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[vietj]

current event loop is not a threading model

[vietj]

I think we should find another way to provide this, e.g. a deployment option boolean that says to reuse the current event loop or something else

[dreamlike-ocean]

I think we should find another way to provide this, e.g. a deployment option boolean that says to reuse the current event loop or something else

I think this is a good idea.let me try

[dreamlike-ocean]

I have reimplemented it according to your idea. Please take a look again.

[vietj]

@dreamlike-ocean thanks I am still wondering if that should not be done diffently using a deployment builder like structure that would allow to pass a context explicitely instead

[dreamlike-ocean]

@dreamlike-ocean thanks I am still wondering if that should not be done diffently using a deployment builder like structure that would allow to pass a context explicitely instead

What if it is implemented using a special verticle type? For example, we can provide an “abstract class ResuseEventLoopVerticle extends AbstractVerticle” type?