Avoid unnecessary call to ‘continueWithBlock:’ when a task is completed

[BrunoBerisso]

When a continuation block is executed with a BFExecutor the internal block that makes the actual call check if the continuation block returns a BFTask, if that is the case a call to continueWithBlock: is made and the completion source is updated accordingly to the result of the task.

This pull request add code to check if the returned task is complete and update the completion source without made an extra call to continueWithBlock:. This increase the performance on memory consumption and execution time. And also make sence :)

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[josephearl]

LGTM

[nlutsenko]

Took a while to get to, so sorry...
Will merge in tomorrow. Feel free to fix that one nit in the meantime.

[BrunoBerisso]

Hey, sorry for the delay on the completed / isCompleted. Should i open another pull request for this?

I think i choose isComplete to avoid access the inner _completed ivar bypassing the resultTask lock. Maybe i should use [resultTask isCompleted] instead the dot syntax.

[nlutsenko]

resultTask.completed will go through using isComplete as it's a property access. resultTask->_isCompleted will use an ivar :D

You are more than welcome to open another pull request to use resultTask.completed. 👍

[BrunoBerisso]

Got it, i don't use getter - setters to much :P
Thanks for the explanation, the new pull request is open.

Thanks for your awesome work with Bolts.

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@BrunoBerisso updated the pull request.

[BrunoBerisso]

Not sure what I supposed to do here.

[nlutsenko]

@BrunoBerisso, completely discard that message. Our GitHub bot went nuts a little bit yesterday.
We calmed him down and restrained him for now, so we don't get mass spam in future.