Implement live internal latency tracker

[gnawf]

Adds a live internal latency tracker so we can emit internal latency metrics.

[github-actions]

Test Results

  135 files  + 2  135 suites  +2   57s ⏱️ +2s
1 010 tests +12  945 ✅ +12  65 💤 ±0  0 ❌ ±0 
1 018 runs  +12  953 ✅ +12  65 💤 ±0  0 ❌ ±0 

Results for commit c395dc4. ± Comparison against base commit 0025f15.

This pull request removes 1 and adds 13 tests. Note that renamed tests count towards both.

graphql.nadel.engine.instrumentation.NadelInstrumentationTimerTest ‑ combines times together

graphql.nadel.NadelStopwatchTest ‑ invoking start running stopwatch does nothing()
graphql.nadel.NadelStopwatchTest ‑ invoking stop on stopped stopwatch does nothing()
graphql.nadel.NadelStopwatchTest ‑ returns elapsed time if stopwatch is still running()
graphql.nadel.NadelStopwatchTest ‑ returns zero if stopwatch is never started()
graphql.nadel.NadelStopwatchTest ‑ stopwatch can be resumed()
graphql.nadel.NadelStopwatchTest ‑ stopwatch elapsed is frozen when stopped()
graphql.nadel.engine.instrumentation.NadelInstrumentationTimerTest ‑ takes the highest time in a batch
graphql.nadel.time.NadelInternalLatencyTrackerImplTest ‑ keeps internal latency paused if there are still external calls pending()
graphql.nadel.time.NadelInternalLatencyTrackerImplTest ‑ stops time as code is running()
graphql.nadel.time.NadelInternalLatencyTrackerImplTest ‑ stops time as future is running()
…

♻️ This comment has been updated with latest results.

[gnawf]

Latency tracker is per request & will be passed in by the caller.

[bbakerman]

why is this elapsed not 100?

[bbakerman]

Ahh I see ignore me