Support telemetry batching and move WebSocket handling to worker

[akhenry]

Closes #7390

Describe your changes:

• Implements new BatchingWebSocket class which handles a lot of boilerplate involved in initiating and managing WebSockets from inside a worker. This is intended as a convenience for Telemetry Providers. More detailed documentation is coming here.
• Modifies the Telemetry API to allow views to optionally specify a strategy when subscribing to telemetry. The supported strategies are:
  • latest - This is the default strategy. The latest strategy will always return the most recent value for a given telemetry point. Depending upon the implementation details of the telemetry provider, for performance reasons a telemetry provider may drop intermediate telemetry values in order to prioritize the latest value when using the latest strategy. This is appropriate for Alphanumeric views, LAD Tables, etc.
  • batch - The batch strategy invokes subscription callbacks with an array containing all of the telemetry values received since the last batch. This strategy is used by plots and tables, where intermediate values matter and should not typically be discarded.
• Modifies plots and tables to accept a batch of telemetry values as an array, where supported by the telemetry provider.

Note on the worker implementation

The worker implementation uses ES6 classes to organize the code, but because of the method used to inline the worker all of the classes have to be in the same file. I am open to suggestions on how to inline workers in a cleaner way.

Note on backwards compatibility

The changes in this PR are intended to be entirely backwards compatible. The BatchingWebSocket and the new batching subscribe strategy are opt-in. Any incompatibilities discovered should be treated as bugs.

All Submissions:

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Is this change backwards compatible? For example, developers won't need to change how they are calling the API or how they've extended core plugins such as Tables or Plots.

Author Checklist

• Changes address original issue?
• Tests included and/or updated with changes? Unit tests included. Issue filed for additional testing backfill here.
• Has this been smoke tested?
• Have you associated this PR with a type: label? Note: this is not necessarily the same as the original issue.
• Have you associated a milestone with this PR? Note: leave blank if unsure.
• Is this a breaking change to be called out in the release notes?
• Testing instructions included in associated issue OR is this a dependency/testcase change?

Reviewer Checklist

• Changes appear to address issue?
• Reviewer has tested changes by following the provided instructions?
• Changes appear not to be breaking changes?
• Appropriate automated tests included?
• Code style and in-line documentation are appropriate?

[codecov]

Codecov Report

Attention: 161 lines in your changes are missing coverage. Please review.

Comparison is base (0eea2e0) 55.82% compared to head (cdf549b) 55.52%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7391      +/-   ##
==========================================
- Coverage   55.82%   55.52%   -0.31%     
==========================================
  Files         666      668       +2     
  Lines       26514    26701     +187     
  Branches     2585     2585              
==========================================
+ Hits        14801    14825      +24     
- Misses      10998    11160     +162     
- Partials      715      716       +1     

Flag	Coverage Δ		*Carryforward flag
e2e-full	41.75% <ø> (-0.07%)	⬇️	Carriedforward from b93647b
e2e-stable	59.10% <20.90%> (-0.69%)	⬇️
unit	48.60% <26.36%> (-0.26%)	⬇️

*This pull request uses carry forward flags. Click here to find out more.

Files	Coverage Δ
src/api/telemetry/TelemetryCollection.js	84.84% <100.00%> (+0.15%)	⬆️
src/plugins/plot/configuration/Model.js	92.85% <ø> (ø)
src/plugins/plot/configuration/PlotSeries.js	85.12% <100.00%> (+0.15%)	⬆️
src/plugins/remoteClock/RemoteClock.js	84.78% <100.00%> (+1.80%)	⬆️
src/api/telemetry/TelemetryAPI.js	89.21% <91.66%> (-0.15%)	⬇️
src/api/telemetry/BatchingWebSocket.js	2.85% <2.85%> (ø)
src/api/telemetry/WebSocketWorker.js	0.00% <0.00%> (ø)

... and 2 files with indirect coverage changes

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[scottbell]

Nice work @akhenry! I'm putting a general code review here, but will check this code against YAMCS in the other PR for more thorough testing. I had a few questions below.

[akhenry]

Review comments addressed, just doing some regression testing...

[akhenry]

Review comments addressed, just doing some regression testing...

Done, ready for re-review.

[scottbell]

Tested again and works great!

[unlikelyzero]

Blocked on legit test failure