Avoid ECONNRESET errors on idle timeout

[gsoldevila]

Summary

Address #82002 and #75440

I think I found a breakthrough for this flaky behavior. I run the integration test 800x locally, with different settings:

Adjusting both the delayed emission (send 1 char at a time), and the socket idle timeout to have exacly the same value (e.g. 10 millis), I managed to get the ECONNRESET 100% of the times.

Thus, IIUC the ECONNRESET happens when the client tries to send a character over the socket and at the same time the server responds with the idle timeout.

Adjusting the values so that the delay between character emissions is significantly larger than the idle timeout, e.g. 20 vs 5, I get socket hang up 100% of the times.

Flaky Test Runner Pipeline - 300x 🟢
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/4030

[gsoldevila]

Unskipped the tests related to #75440

Flaky test runner pipeline 100x - 🔴 (1 failure out of 100 runs)
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/3813

Failed test
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/3813#018b8078-fbec-44d4-ade7-4f530d46e433

[gsoldevila]

I updated the tests that intend to send the whole payload straight away, through this commit.
I believe this can help solving the unexpected ECONNRESET.

Flaky test runner pipeline - 200x 🟢
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/3881

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: a33b50b

Failed CI Steps

• x-pack/test_serverless/functional/test_suites/observability/config.ts

Test Failures

• [job] [logs] x-pack/test_serverless/functional/test_suites/observability/config.ts / serverless observability UI Rules list "after each" hook for "should create an ES Query Rule and display it when consumer is observability"
• [job] [logs] x-pack/test_serverless/functional/test_suites/observability/config.ts / serverless observability UI Rules list should create an ES Query Rule and display it when consumer is observability

Metrics [docs]

✅ unchanged

History

• 💔 Build #176846 failed ab4dac8
• 💛 Build #172968 was flaky c224a566085ed372f7e18b65fb9045a8aeb5ae14
• 💛 Build #171842 was flaky ef90dd44574089fff70791bfa353671ff93a8649
• 💚 Build #171300 succeeded 65d8684ba8de8bc6b69bb134a12ddcf3ed8bcfc3
• 💔 Build #161597 failed 69a1d0c0a0d51ad52239f060fc77707c7c02de65

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[TinaHeiligers]

Good work! Let's give it a try and see what happens. FYI, Builkite's got issues ATM, see https://www.buildkitestatus.com/