subscription_thread_dispatcher: guard against duplicate room events #291

Job	Run time
Detect Changes	5s
Link Check / Link Check	12s
License Check / License Check	7s
Generate Docs / Generate and verify docs	25s
C++ Checks / clang-format	15s
Builds / Build (macos-x64)	15m 25s
Builds / Build (linux-x64)	7m 5s
Builds / Build (macos-arm64)	4m 19s
Builds / Build (windows-x64)	12m 3s
Tests / Test (linux-arm64)	11m 33s
Tests / Test (linux-x64)	9m 11s
Builds / Build (linux-arm64)	8m 49s
Tests / Test (macos-x64)	16m 44s
Tests / Test (windows-x64)	4m 2s
Tests / Code Coverage	16m 50s
C++ Checks / clang-tidy	11m 49s
Tests / Test (macos-arm64)	9m 10s
Docker Images	0s
Rust Release Check	0s
CI	5s
	2h 8m 9s

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