Add FromChannelWithContext()

[kalaninja]

resolves #93

[ahmetb]

Why don't we just do ctx instead? That way we support any form of cancellation not just time.

[kalaninja]

I added FromChannelWithContext method and kept FromChannelWithTimeout for convenience, but I am not sure it is really needed. wdyt?

[ahmetb]

I think we should just remove the Timeout one. It's fairly easy to implement given ctx signature is offered on another method.

[kalaninja]

I think we should just remove the Timeout one. It's fairly easy to implement given ctx signature is offered on another method.

Yes, very much agree, had a similar feeling.

UPDATE: Though we can slightly change FromChannelWithTimeout behavior in a way that might be hard to achieve with FromChannelWithContext. FromChannelWithTimeout can start the timer when iteration starts (opposite to when Query is created). I am not sure if it is needed though.

[ahmetb]

I think it's fine to just have the ctx version. Typically if someone has a deadline it applies to the whole thing not when we start iterating.