Defer pool duration telemetry instruments

[ChiragAgg5k]

Summary

• Upgrade utopia-php/telemetry to ^0.4 so pools can use lazy instrument factories.
• Defer registration of pool wait/use duration histograms until their first record.
• Keep steady-state pool gauges eager and add tests that lock in eager gauge vs lazy histogram behavior.

Testing

• composer check
• composer lint
• ./vendor/bin/phpunit --configuration phpunit.xml --filter 'testPoolTelemetry|testPoolUseDurationTelemetryIsCreatedOnFirstUse'
• composer audit

Notes

• Full composer test exits with code 139 in the existing Utopia\Tests\Adapter\SwooleTest::testSwooleCoroutineStressTest after the new telemetry tests pass in both Stack and Swoole runs.

[greptile-apps]

Greptile Summary

This PR defers registration of the pool.connection.wait_time and pool.connection.use_time histogram instruments until their first record() call by switching from $telemetry->createHistogram() to Histogram::lazy(), while keeping the four pool-state gauges eager. The utopia-php/telemetry dependency is also pinned to ^0.4 to match the new API.

• Lazy histograms: both duration histograms are now created on the first pop() / use() call respectively, avoiding unnecessary instrument registration in pools that are configured but never exercised.
• Eager gauges unchanged: open, active, idle, and capacity gauges continue to register at setTelemetry() time.
• New tests: testPoolTelemetry gains assertions locking in the eager-gauge / lazy-histogram split; testPoolUseDurationTelemetryIsCreatedOnFirstUse verifies use_time appears only after the first use() call.

Confidence Score: 5/5

Safe to merge — the change is narrow, well-tested, and the lazy-init path is exercised by both the stack and Swoole test runs.

The logic change is confined to two Histogram::lazy() calls in setTelemetry(); all downstream record() call sites are untouched. The new tests verify the exact eager-vs-lazy boundary that this PR introduces, and the gauge behavior is unchanged. No correctness issues were found.

No files require special attention.

Important Files Changed

Filename	Overview
src/Pools/Pool.php	Replaces eager createHistogram() calls for wait_time and use_time with Histogram::lazy() so both instruments are only registered in the backend on first record() call; gauge creation remains eager as before.
tests/Pools/Scopes/PoolTestScope.php	Adds assertions to testPoolTelemetry verifying gauges are created immediately while histograms are absent until first use; adds testPoolUseDurationTelemetryIsCreatedOnFirstUse covering the happy-path lazy init of use_time.
composer.json	Pins utopia-php/telemetry to ^0.4 (was "*"), tightening the version constraint to match the new Histogram::lazy() API.
composer.lock	Routine dependency bumps across open-telemetry/, symfony/, phpunit/* packages, and utopia-php/telemetry 0.2.0 → 0.4.0.

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