Get NIOEmbedded clean under strict concurrency #1116

Job	Run time
Construct integration test matrix	4s
Vsock tests	2m 21s
Benchmarks / Construct Benchmarks matrix	3s
Cxx interop / Construct Cxx interop matrix	5s
Unit tests / Construct unit test matrix	3s
Soundness / API breakage check	2m 5s
Soundness / Documentation check	2m 15s
Soundness / Unacceptable language check	5s
Soundness / Broken symlinks check	5s
Soundness / Format check	53s
Soundness / License headers check	9s
Soundness / Shell check	35s
Soundness / YAML lint check	4s
Soundness / Python lint check	6s
Benchmarks / Benchmarks / Linux (5.9)	5m 29s
Benchmarks / Benchmarks / Linux (5.10)	5m 2s
Benchmarks / Benchmarks / Linux (6.0)	5m 53s
Benchmarks / Benchmarks / Linux (nightly-6.0)	5m 55s
Benchmarks / Benchmarks / Linux (nightly-main)	4m 30s
Unit tests / Unit tests / Linux (5.9)	3m 48s
Unit tests / Unit tests / Linux (5.10)	3m 49s
Unit tests / Unit tests / Linux (6.0)	4m 3s
Unit tests / Unit tests / Linux (nightly-6.0)	4m 34s
Unit tests / Unit tests / Linux (nightly-main)	4m 38s
Integration tests / Linux (5.9)	15m 27s
Integration tests / Linux (5.10)	14m 11s
Integration tests / Linux (6.0)	16m 16s
Integration tests / Linux (nightly-6.0)	16m 41s
Integration tests / Linux (nightly-main)	16m 44s
Cxx interop / Cxx interop / Linux (5.9)	1m 12s
Cxx interop / Cxx interop / Linux (5.10)	1m 12s
Cxx interop / Cxx interop / Linux (6.0)	1m 25s
Cxx interop / Cxx interop / Linux (nightly-6.0)	1m 37s
Cxx interop / Cxx interop / Linux (nightly-main)	1m 47s
	2h 23m 6s

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