Make the ResponseAccumulator Sendable #134

Job	Run time
Unit tests / Construct unit test matrix	4s
Cxx interop / Construct Cxx interop matrix	5s
Soundness / API breakage check	4m 26s
Soundness / Format check	40s
Soundness / Broken symlinks check	8s
Soundness / Documentation check	2m 50s
Soundness / License headers check	4s
Soundness / Shell check	34s
Soundness / Python lint check	4s
Soundness / Unacceptable language check	5s
Soundness / YAML lint check	4s
Static SDK / Static SDK / Linux (latest-release Jammy)	3m 35s
Static SDK / Static SDK / Linux (main Jammy)	2m 18s
Cxx interop / Cxx interop / Linux (5.10)	2m 30s
Cxx interop / Cxx interop / Linux (6.0)	2m 46s
Cxx interop / Cxx interop / Linux (6.1)	2m 56s
Cxx interop / Cxx interop / Linux (nightly-next)	3m 30s
Cxx interop / Cxx interop / Linux (nightly-main)	3m 48s
Unit tests / Unit tests / Linux (5.10)	4m 43s
Unit tests / Unit tests / Linux (6.0)	5m 20s
Unit tests / Unit tests / Linux (6.1)	4m 57s
Unit tests / Unit tests / Linux (nightly-next)	5m 44s
Unit tests / Unit tests / Linux (nightly-main)	5m 49s
	57m 0s

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