Handle stream operations

[vertexclique]

• [ ] group_by
• [ ] items: iterate over both key and value at the same time
• [ ] events: access raw events
• [ ] take: buffer up specific amount of values from a stream
• [ ] enumerate: count values
• [ ] through: forward through yet another topic/stream.
• [ ] filter: filter values to omit from stream
• [ ] echo: repeat to one or more topics.
• [ ] and other ordinary iterators that can be inherited from Iterators/futures::Stream.

[nicor88]

For take operations will be nice to handle both amount of record and within timeout, to avoid to stale processing when the amount of values is not reached.

[vertexclique]

I didn't quite get it. What do you mean by stale processing when values aren't raced?

[nicor88]

@vertexclique check the implementation of take on faust. It supports an amount of records, in combination with a parameter called within.

Imaging to have a stream.take(100).

The problem with the above code is that it will block forever if there are 99 messages and the last hundredth message is never received. To solve this add a within timeout so that up to 100 values will be processed within 10 seconds.

cit.

So it will be nice to have such feature in callysto too.

[vertexclique]

ok makes sense.