[split] Finagle: Make blockingOperation in FuturePool example lazy.
[split] Finagle: Make blockingOperation in FuturePool example lazy.

Using a val in the example nullifies the intended parallelism. Made
`blockingOperation` a def to exemplify lazy evalution.

RB_ID=71569

svetlyak40wt/finagle,lucaslanger/finagle,fengshao0907/finagle,nomadlabs/finagle,sveinnfannar/finagle,fengshao0907/finagle,svetlyak40wt/finagle,cogitate/twitter-finagle-uuid,olix0r/finagle,adriancole/finagle,thirstycrow/finagle,liamstewart/finagle,OopsOutOfMemory/finagle,scorpiovn/finagle,cogitate/twitter-finagle-uuid,mkhq/finagle,adriancole/finagle,suls/finagle,BuoyantIO/finagle,koshelev/finagle,almendar/finagle,chen0031/finagle,olix0r/finagle,thirstycrow/finagle,nkhuyu/finagle,jamescway/finagle,kristofa/finagle,latur19318/finagle,suls/finagle,Krasnyanskiy/finagle,nomadlabs/finagle,rojanu/finagle,sveinnfannar/finagle,kumasento/finagle,LithiumTD/finagle,nomadlabs/finagle,liamstewart/finagle,kingtang/finagle,thirstycrow/finagle,almendar/finagle,rojanu/finagle,adriancole/finagle,sveinnfannar/finagle,spockz/finagle,jamescway/finagle,nkhuyu/finagle,mosesn/finagle,koshelev/finagle,latur19318/finagle,jeremyrsmith/finagle,spockz/finagle,almendar/finagle,mkhq/finagle,mosesn/finagle,jay-johnson/finagle,lysu/finagle,almendar/finagle,luciferous/finagle,latur19318/finagle,firebase/finagle,jeremyrsmith/finagle,Krasnyanskiy/finagle,adriancole/finagle,folone/finagle,lucaslanger/finagle,rjbhewei/finagle,BuoyantIO/finagle,nomadlabs/finagle,lukiano/finagle,jeremyrsmith/finagle,luciferous/finagle,bruceluo/finagle,liamstewart/finagle,zfy0701/finagle,a-manumohan/finagle,lucaslanger/finagle,jpederzolli/finagle,mkhq/finagle,kingtang/finagle,rjbhewei/finagle,adriancole/finagle,nkhuyu/finagle,a-manumohan/finagle,twitter/finagle,lysu/finagle,mkhq/finagle,latur19318/finagle,BuoyantIO/finagle,lukiano/finagle,bruceluo/finagle,rjbhewei/finagle,chen0031/finagle,lucaslanger/finagle,bruceluo/finagle,bruceluo/finagle,almendar/finagle,travisbrown/finagle,lukiano/finagle,zfy0701/finagle,chen0031/finagle,rjbhewei/finagle,firebase/finagle,OopsOutOfMemory/finagle,svetlyak40wt/finagle,kristofa/finagle,kumasento/finagle,mosesn/finagle,nkhuyu/finagle,BuoyantIO/finagle,LithiumTD/finagle,suls/finagle,luciferous/finagle,jay-johnson/finagle,svetlyak40wt/finagle,foursquare/finagle,jay-johnson/finagle,rodrigodealer/finagle,lysu/finagle,fengshao0907/finagle,scorpiovn/finagle,nkhuyu/finagle,kingtang/finagle,thirstycrow/finagle,lysu/finagle,latur19318/finagle,kingtang/finagle,folone/finagle,jpederzolli/finagle,luciferous/finagle,stevegury/finagle,Krasnyanskiy/finagle,kristofa/finagle,fengshao0907/finagle,rojanu/finagle,rodrigodealer/finagle,suls/finagle,jeremyrsmith/finagle,rojanu/finagle,sveinnfannar/finagle,jeremyrsmith/finagle,Krasnyanskiy/finagle,suls/finagle,jay-johnson/finagle,koshelev/finagle,firebase/finagle,olix0r/finagle,stevegury/finagle,a-manumohan/finagle,a-manumohan/finagle,thirstycrow/finagle,lysu/finagle,jpederzolli/finagle,kingtang/finagle,rodrigodealer/finagle,lukiano/finagle,travisbrown/finagle,travisbrown/finagle,zfy0701/finagle,scorpiovn/finagle,kumasento/finagle,spockz/finagle,twitter/finagle,olix0r/finagle,lucaslanger/finagle,jpederzolli/finagle,BuoyantIO/finagle,mkhq/finagle,scorpiovn/finagle,foursquare/finagle,BuoyantIO/finagle,zfy0701/finagle,cogitate/twitter-finagle-uuid,lukiano/finagle,mkhq/finagle,fengshao0907/finagle,folone/finagle,lukiano/finagle,chen0031/finagle,jamescway/finagle,spockz/finagle,sveinnfannar/finagle,luciferous/finagle,twitter/finagle,nomadlabs/finagle,kumasento/finagle,stevegury/finagle,twitter/finagle,LithiumTD/finagle,cogitate/twitter-finagle-uuid,jpederzolli/finagle,LithiumTD/finagle,firebase/finagle,koshelev/finagle,twitter/finagle,rodrigodealer/finagle,LithiumTD/finagle,liamstewart/finagle,travisbrown/finagle,folone/finagle,svetlyak40wt/finagle,rojanu/finagle,adriancole/finagle,OopsOutOfMemory/finagle,kumasento/finagle,scorpiovn/finagle,Krasnyanskiy/finagle,sveinnfannar/finagle,chen0031/finagle,kristofa/finagle,OopsOutOfMemory/finagle,rjbhewei/finagle,jay-johnson/finagle,foursquare/finagle,rodrigodealer/finagle,mosesn/finagle,kristofa/finagle,foursquare/finagle,OopsOutOfMemory/finagle,liamstewart/finagle,travisbrown/finagle,bruceluo/finagle,koshelev/finagle,firebase/finagle,spockz/finagle,foursquare/finagle,luciferous/finagle,stevegury/finagle,koshelev/finagle,folone/finagle,a-manumohan/finagle,jamescway/finagle,jamescway/finagle,mosesn/finagle,cogitate/twitter-finagle-uuid,spockz/finagle,zfy0701/finagle