Measure pending time in Executors

Is your feature request related to a problem? Please describe.

What do you think about adding instrumentation to Executors which will measure, how long tasks are being stucked in a queue?
For example, right now in Spring applications, depending on configuration, it may happen that:

client metric tells 20s, while in reality it was 10s
server metric tells 5s, while in reality it was 10s

Reason for that it's very simple: Thread Pool Saturation.
From my experience I would say, that libraries, frameworks measure usually number of tasks, but... is 10 high? or maybe 1_000_000? That's why pending time seems in my opinion like something very useful

Here some reproducible example for Spring Application
https://github.com/spring-projects/spring-framework/issues/35302

Describe the solution you'd like

the whole idea is to have something like this

class MonitoredExecutor internal constructor(private val delegate: Executor) : Executor {
	override fun execute(runnable: Runnable) {
		delegate.execute(MonitoredRunnable(runnable))
	}
}

class MonitoredRunnable internal constructor(private val delegate: Runnable) : Runnable {
	private val startTime = System.nanoTime()

	override fun run() {
		val duration = Duration.ofNanos(System.nanoTime() - startTime)
		SomeLogger.log(this, "WORKAROUND Http server pending request took: $duration")

		delegate.run()
	}
}

Describe alternatives you've considered

No response

Additional context

I'm opening this issue in Java repository, but I think it's applicable probably for any other programming language

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Start by tracing the repository's Executor instrumentation entry point and compare it with the Kotlin MonitoredExecutor example and the linked Spring reproduction. Before implementation, clarify which executors and metric semantics are in scope; done should include a defined pending-time measurement and verification for the supported cases.