Add ws heartbeat

[mxiao-cll]

Add ability for EA to send heartbeat to ws server

Tested this on dxFeed EA and verified that regular heartbeat was sent periodically

[github-actions]

👋 mxiao-cll, thanks for creating this pull request!

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[github-actions]

NPM Publishing labels 🏷️

🟢 This PR has valid version labels and will cause a patch bump.

[dskloetc]

Can you add something in the PR description about how you've tested this in an actual EA?

[mohamed-mehany]

Code looks good to me.
However, was wondering if we should also add a ping handler since WS servers usually already send regular pings, and would be nice to be able to use that handler to keep the WS connection alive and prevent the framework from closing the connection?

[mxiao-cll]

Code looks good to me. However, was wondering if we should also add a ping handler since WS servers usually already send regular pings, and would be nice to be able to use that handler to keep the WS connection alive and prevent the framework from closing the connection?

You mean a handler to handle ping events sent by the WS server? We can add that, but for this one I have a use case where a specific message needs to be sent to server to keep connection open.

[github-actions]

🚀 Successfully created version bump PR: #641