Get NIOEmbedded clean under strict concurrency #1112

Job	Run time
Construct integration test matrix	6s
Vsock tests	2m 7s
Cxx interop / Construct Cxx interop matrix	4s
Benchmarks / Construct Benchmarks matrix	2s
Unit tests / Construct unit test matrix	3s
Soundness / API breakage check	2m 9s
Soundness / Documentation check	2m 10s
Soundness / License headers check	10s
Soundness / Unacceptable language check	1s
Soundness / Broken symlinks check	2s
Soundness / Format check	49s
Soundness / Shell check	45s
Soundness / Python lint check	31s
Soundness / YAML lint check	8s
Benchmarks / Benchmarks / Linux (5.9)	5m 18s
Benchmarks / Benchmarks / Linux (5.10)	5m 0s
Benchmarks / Benchmarks / Linux (6.0)	5m 23s
Benchmarks / Benchmarks / Linux (nightly-6.0)	6m 39s
Benchmarks / Benchmarks / Linux (nightly-main)	4m 32s
Unit tests / Unit tests / Linux (5.9)	3m 51s
Unit tests / Unit tests / Linux (5.10)	3m 52s
Unit tests / Unit tests / Linux (6.0)	4m 11s
Unit tests / Unit tests / Linux (nightly-6.0)	4m 47s
Unit tests / Unit tests / Linux (nightly-main)	4m 32s
Cxx interop / Cxx interop / Linux (5.9)	1m 21s
Cxx interop / Cxx interop / Linux (5.10)	1m 13s
Cxx interop / Cxx interop / Linux (6.0)	1m 22s
Cxx interop / Cxx interop / Linux (nightly-6.0)	1m 38s
Cxx interop / Cxx interop / Linux (nightly-main)	1m 44s
Integration tests / Linux (5.9)	15m 45s
Integration tests / Linux (5.10)	14m 18s
Integration tests / Linux (6.0)	16m 16s
Integration tests / Linux (nightly-6.0)	16m 59s
Integration tests / Linux (nightly-main)	16m 44s
	2h 24m 32s

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