[APPSEC-56614] Add Instrumentation::Gateway#pushed? method

[Strech]

What does this PR do?

Adds a method to check wether event with specific name was already ever pushed or not

Motivation:

I need a way to react on one event only if another event was pushed before. To make it very straightforward I decided to allow a simple check - was an event published or not.

Change log entry

No. Internal change

Additional Notes:

The whole Instrumentation::Gateway is a subject to rewrite, but the core logic of "I want to know about what kind of events were pushed" remains.

How to test the change?

CI is good enough.

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-03-06 10:32:20

Comparing candidate commit 241d169 in PR branch appsec-56614-track-triggered-instrumentation-events with baseline commit 2f427f8 in branch master.

Found 1 performance improvements and 0 performance regressions! Performance is the same for 30 metrics, 2 unstable metrics.

scenario:profiler - Allocations ()

• 🟩 throughput [+195396.272op/s; +213426.359op/s] or [+6.278%; +6.857%]

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.69%. Comparing base (2f427f8) to head (241d169).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4459      +/-   ##
==========================================
- Coverage   97.70%   97.69%   -0.01%     
==========================================
  Files        1375     1376       +1     
  Lines       83812    83824      +12     
  Branches     4251     4251              
==========================================
+ Hits        81887    81894       +7     
- Misses       1925     1930       +5     

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[datadog-datadog-prod-us1]

Datadog Report

Branch report: appsec-56614-track-triggered-instrumentation-events
Commit report: 241d169
Test service: dd-trace-rb

✅ 0 Failed, 20623 Passed, 1374 Skipped, 3m 12.93s Total Time