perf: CUDA async to host copy #6085

Performance Regression: -31.44%

⚡ 4 improved benchmarks
❌ 3 regressed benchmarks
✅ 1247 untouched benchmarks
⏩ 1254 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
❌	Simulation	`canonical_into_non_nullable[(10000, 10, 0.01)]`	219.7 µs	308.6 µs	-28.82%
⚡	Simulation	`canonical_into_non_nullable[(10000, 1, 0.01)]`	44.4 µs	37.1 µs	+19.5%
⚡	Simulation	`canonical_into_non_nullable[(10000, 1, 0.1)]`	59.4 µs	53.2 µs	+11.61%
❌	Simulation	`canonical_into_non_nullable[(10000, 10, 0.0)]`	192.9 µs	281.4 µs	-31.44%
⚡	Simulation	`canonical_into_non_nullable[(10000, 1, 0.0)]`	38.9 µs	31.8 µs	+22.45%
❌	Simulation	`canonical_into_non_nullable[(10000, 10, 0.1)]`	375.4 µs	468 µs	-19.78%
⚡	Simulation	`canonical_into_nullable[(10000, 100, 0.0)]`	5.1 ms	4.1 ms	+24.85%

_{Comparing ad/async-copy (afbc61c) with develop (1a0d672)}

1254 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩