Add globalTimeout operation on Flowable.

[newkek]

Hi,

While working on a project where we needed to set a finite timeout bound to a flowable and error out if the timeout was reached, I wasn't able to find an operation that would be able to do that in the Flowable class. Only .timeout() is available but it is to specify a timeout between each item, not the global Flowable.

After some help from the mailing list I ended up using originalFlowable.takeUntil(Flowable.never().timeout()) which works very well for the intended purpose (shout-out to David from the mailing list who came up with it).
I think it would be valuable to other users who aren't aware of the takeUntil(Publisher) method, to have this operation available in the library. Please let me know if you think it would be useful as well.

I've included a simple unit test as well as Javadocs as best as I could, however I didn't know how to generate a marble schema...

Thanks.

[akarnokd]

shout-out to David from the mailing list who came up with it

And the same David will close this PR for two reasons: 1) the functionality can be achieved with a small set of existing operators, and 2) please open an issue to discuss feature requests first so that time is not wasted on either end.

[newkek]

Ha - didn't realize @akarnokd was the David from the ML... 🤦‍♂️

Fair enough, although I thought this would be ok considering I've seen other methods in the Flowable class that are simple shortcuts to other operations, example: Flowable.merge(), Flowable.mergeArray(), startWith(), etc.. does that make sense?

Thanks for the quick reply. On both the ML and here.