refactor: flag fixed queue internal storage data structure readonly #1328

Job	Run time
Deno canary on windows-latest	1m 8s
Deno v1.x on ubuntu-latest	1m 16s
Deno canary on ubuntu-latest	1m 24s
Deno canary on macos-latest	3m 29s
Deno v2.x on macos-latest	51s
Deno v1.x on macos-latest	1m 0s
Deno v2.x on ubuntu-latest	2m 6s
Deno v2.x on windows-latest	1m 13s
Deno v1.x on windows-latest	1m 11s
	13m 38s

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