feat: Instrument thread pools

[SanjayVas]

No description provided.

[wfa-reviewable]

This change is 

[stevenwarejones]

Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @SanjayVas)

[stevenwarejones]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @SanjayVas)

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src/main/kotlin/org/wfanet/measurement/common/Instrumentation.kt line 57 at r1 (raw file):

  /** Registers the specified thread pool for instrumentation. */
  fun registerThreadPool(poolName: String, threadPool: ThreadPoolExecutor) {

this should get a test

[stevenwarejones]

Reviewed 2 of 2 files at r2, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @SanjayVas)

[SanjayVas]

Reviewable status: 2 of 11 files reviewed, 1 unresolved discussion (waiting on @stevenwarejones)

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src/main/kotlin/org/wfanet/measurement/common/Instrumentation.kt line 57 at r1 (raw file):

Previously, stevenwarejones (Steven Ware Jones) wrote…

this should get a test

Done.

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src/main/kotlin/org/wfanet/measurement/common/Instrumentation.kt line 35 at r3 (raw file):

  /** Singleton [OpenTelemetry] instance which may be initialized by the Java agent. */
  val openTelemetry: OpenTelemetry by lazy {
    // Using lazy delegate to avoid accessing global instance before it's initialized.

Refactored this a bit to avoid having GlobalOpenTelemetry.get() called during static initialization. PTAL

[stevenwarejones]

Reviewed 8 of 10 files at r3, 1 of 3 files at r4, 2 of 6 files at r5, all commit messages.
Reviewable status: 9 of 13 files reviewed, 2 unresolved discussions (waiting on @SanjayVas)

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src/main/kotlin/org/wfanet/measurement/common/InvalidatableLazy.kt line 20 at r4 (raw file):

/** [Lazy] which can be invalidated. */
class InvalidatableLazy<T> internal constructor(private val initializer: () -> T) : Lazy<T> {

needs a test

[SanjayVas]

Reviewable status: 9 of 13 files reviewed, 2 unresolved discussions (waiting on @stevenwarejones)

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src/main/kotlin/org/wfanet/measurement/common/InvalidatableLazy.kt line 20 at r4 (raw file):

Previously, stevenwarejones (Steven Ware Jones) wrote…

needs a test

Done.

[stevenwarejones]

Reviewed 2 of 6 files at r5, 1 of 2 files at r6.
Reviewable status: 11 of 14 files reviewed, all discussions resolved

[SanjayVas]

Reviewed 2 of 6 files at r5, 1 of 2 files at r6.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @SanjayVas)