Simplify implementation of Dispatch-async bridge #165

Job	Run time
cmake-smoke-test / Linux (nightly-main - noble)	5m 21s
cmake-smoke-test / macOS (Xcode ${{ matrix.xcode_version }} - ${{ matrix.os_version }} - ${{ matrix.arch }})	0s
Test / macOS (Xcode ${{ matrix.xcode_version }} - ${{ matrix.os_version }} - ${{ matrix.arch }})	0s
Test / Linux (nightly-main - noble)	29m 33s
Test / Windows (nightly-main - windows-2019)	29m 38s
Test / Linux (nightly-main - jammy)	29m 33s
Test / Linux (nightly-main - focal)	29m 33s
Test / Linux (nightly-main - rhel-ubi9)	29m 33s
Test / Linux (nightly-6.2 - noble)	29m 32s
Test / Linux (nightly-6.2 - jammy)	29m 33s
Test / Linux (nightly-6.2 - focal)	29m 33s
Test / Linux (nightly-6.2 - rhel-ubi9)	29m 34s
Soundness / API breakage check	0s
Soundness / Broken symlinks check	6s
Soundness / Documentation check	41s
Soundness / Format check	0s
Soundness / License headers check	16s
Soundness / Python lint check	6s
Soundness / Shell check	34s
Soundness / Unacceptable language check	4s
Soundness / YAML lint check	5s
	4h 33m 15s

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