subscription_thread_dispatcher: guard against duplicate room events #266

Job	Run time
Detect Changes	7s
Link Check / Link Check	8s
License Check / License Check	5s
C++ Checks / clang-tidy	11m 9s
Tests / Code Coverage	17m 19s
Builds / Build (macos-x64)	13m 20s
C++ Checks / clang-format	17s
Builds / Build (macos-arm64)	4m 19s
Builds / Build (windows-x64)	10m 11s
Generate Docs / Generate and verify docs	23s
Builds / Build (linux-x64)	9m 6s
Tests / Test (linux-arm64)	9m 52s
Tests / Test (macos-x64)	13m 48s
Tests / Test (linux-x64)	11m 13s
Tests / Test (windows-x64)	14m 22s
Tests / Test (macos-arm64)	8m 15s
Builds / Build (linux-arm64)	7m 53s
Docker Images	0s
Rust Release Check	0s
CI	5s
	2h 11m 52s

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