Refactor packages: review `AnnounceEvent` struct #2690

Job	Run time
Build on ubuntu-latest (nightly)	3m 20s
Build on ubuntu-latest (stable)	3m 26s
Build on macos-latest (nightly)	4m 39s
Build on macos-latest (stable)	5m 26s
Build on windows-latest (nightly)	7m 8s
Build on windows-latest (stable)	8m 3s
Formatting	18s
Static Analysis (nightly)	1m 58s
Static Analysis (stable)	1m 57s
Units (nightly)	12m 25s
Units (stable)	13m 10s
E2E (nightly)	20m 32s
E2E (stable)	20m 32s
	1h 42m 54s

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