require SuspendableClassifier Document

[fulai...@cloudcar.com]

Hi everyone, my application contains a lot of Suspendable methods, 

so I am looking for some way use Fiber without @Suspendable or throw SuspendExecution.

I am read `DefaultSuspendableClassifier` source code and 

find it's possible to use `SuspendableClassifier` extension which will loaded by `ServiceLoader`.

I don't know why this feature is not mentioned in quasar document http://docs.paralleluniverse.co/quasar/

can my application dependent on this feature? if answer is true, 

can you give litter document about this feature in that doc site? Thanks!