Intake Protocol V2 POC

[alvarolobato]

POC using the new Intake Protocol V2 from elastic/apm-server#930

[roncohen]

@watson any progress on this?

[watson]

Yes. I expect a POC for the Node.js agent this week. I think it's all kind of working, but the tests are still failing (turns out those have been the most complicated to update as many expect each request to the APM Sever to finish immediately in other to know the test is over 😄)

[watson]

Here's the Node.js agent POC: #465

[watson]

I've created a meta issue to track the overall progress: #471