Allow function to be broadcasted to all or randomly

[Nordes]

Probably would require to be more polished, but the idea here would be to have multiple listener on one function. I didn't test the scenario of multiple zipper or mesh network, but only a simple source + zipper + multi-sfn.

This is only a proposal draft, so don't hesitate to comment. Note that I am fully aware that I will have to remove some comments and improve some part of the code.

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[venjiang]

Thank you for the PR. Let me think about this.🤔

[fanweixiao]

Hi @Nordes , thanks for the PR. I break this to different parts:

📕 Say we have two Stream Functions deals with same data, in YoMo, can be implemented like this:

1. Create sfn-1 which observe data with tag is 0x33
2. Create sfn-2 which did the same as sfn-1

Zipper will route data with tag is 0x33 to sfn-1 and sfn-2 at the same time, so developer can separate their logic to different services and deploy to anywhere they want. This is already supported right now.

📕 Multiple Stream Functions with same name

I think we should get rid of this behavior for unexpected results. @venjiang @xiaojian-hong @wujunzhuo

📕 Source can get response from Zipper instead of implementing a Stream Function besides Source to get the response.

I think YoMo should implement it!

Two years ago, YoMo was created to solve problems for IIoT, most of the scenarios were offloading the processing from devices to the edge clouds. Now, more and more web applications need low-latency and streaming computing, I think we should improve YoMo to meet the requirements.

[fanweixiao]

Hi @Nordes ,

about this feature request:

📕 Multiple Stream Functions with same name

we release YoMo v1.7.3, and avoid sfn with same name.

📕 Source can get response from Zipper instead of implementing a Stream Function besides Source to get the response.

in #330, we are implementing, will release this feature in next 2 weeks :)

[fanweixiao]

Hi @Nordes, about the features:

📕 Source can get response from Zipper instead of implementing a Stream Function besides Source to get the response.

@venjiang implemented in v1.8.0.

Examples about Backflow support can be found at example/5-backflow.

Thanks a lot for contribute new features! as all the features required have been implemented, I think this PR can be closed.