Cancel other promises when one of any composition got fulfilled

[mzaks]

When you do
[OMPromise any:@[A, B, C]];
and e.g. B is fulfilled.
Wouldn't it be cool to cancel A and C.
It's not a big deal, but users may expect such behavior, special when there is a cancel method on promises.
Same is true for progress. If we have an any concatenation, we are done (100% progress) when any of the promises is fulfilled.

[aomader]

I don't think that should be the default behavior. Some people might use one of your combined promises A, B or C also in another context and they would be surprised if it gets canceled.
But we could add a second version of this combinator which adds the option to cancel all remaining promises, something like - any:(NSArray *)promises cancel:(BOOL)cancel;. I think that would be a good addition.
In this context it might also make sense to add a similar addition for the all: combinator, which cancels all other promises in case one fails.