Feat: Virtual DataChannel

[luongngocminh]

Pull Request

Description

Added a virtual datachannel for bi-direction communication between the users in a room. This datachannel is not the same with the WebRTC Datachannel, but it will use the WebRTC Channel to transports the pubsub style messages. A virtual datachannel can be created dynamically via Room Request through the SDK. A Room can have multiple virtual channels.

Checklist

• [x] I have tested the changes locally.
• [x] I have reviewed the code changes.
• [ ] I have updated the documentation, if necessary.
• [x] I have added appropriate tests, if applicable.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 70.19231% with 124 lines in your changes missing coverage. Please review.

Project coverage is 44.65%. Comparing base (c459b13) to head (642b9f1).

Files	Patch %	Lines
packages/transport_webrtc/src/transport/webrtc.rs	0.00%	49 Missing :warning:
packages/media_core/src/endpoint/internal.rs	0.00%	25 Missing :warning:
...ackages/media_core/src/cluster/room/datachannel.rs	91.12%	19 Missing :warning:
packages/media_core/src/cluster/room.rs	31.81%	15 Missing :warning:
packages/protocol/src/protobuf/session.rs	0.00%	7 Missing :warning:
...dia_core/src/cluster/room/datachannel/publisher.rs	80.76%	5 Missing :warning:
...ia_core/src/cluster/room/datachannel/subscriber.rs	97.72%	1 Missing :warning:
packages/protocol/src/datachannel.rs	87.50%	1 Missing :warning:
packages/transport_webrtc/src/transport/whep.rs	0.00%	1 Missing :warning:
packages/transport_webrtc/src/transport/whip.rs	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #327 +/- ## ========================================== + Coverage 43.89% 44.65% +0.76% ========================================== Files 117 121 +4 Lines 12984 13384 +400 ========================================== + Hits 5699 5977 +278 - Misses 7285 7407 +122 ```

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[giangndm]

@luongngocminh can you update the changes in each comments?

[luongngocminh]

@luongngocminh can you update the changes in each comments?

Can you check the changes again I have already updated it

[jibon57]

@luongngocminh nice! So, this could be a replacement of traditional websocket protocol? But how can it handle if subscriber disconnected & later connected again? Will they loose all those messages during disconnected time? Or server will store those & later deliver?

[luongngocminh]

@jibon57 The thought behind this feature is that it's a datachannel, not a message queue or a simple kind of way to do chat applications. It's basically a data delivering passage way, for data to travel around in realtime in a pub/sub manner. So as a developer, you can use these feature APIs to build your own implementation.