Explore multi release jar to leverage Thread.onSpinWait vs. Thread.yield on java 9+

[jack-berg]

#8313 (comment)

[zeitlinger]

Seems wrong fit here. Thread.onSpinWait is a CPU pause hint for ultra-short busy-waits (nanoseconds–microseconds) where the awaited condition is expected to flip almost immediately and a context switch would cost more than the spin. It does not release the CPU.

These two loops are waiting for a peer thread that may be preempted (recorder/new-series operations can take arbitrary time, and the scheduler may have descheduled them). Spinning with onSpinWait on a contended or low-core host risks starving the very thread we're waiting on. Thread.yield() hints the scheduler to run other runnables, which lets the preempted peer make progress — that's why acquireHandleForRecord already uses yield(), and the new spins now do too for consistency.