[Repo Assist] perf/test: replace ConcurrentHashSet with plain HashSet in except; add zip/indexed tests#292

dsyme merged 3 commits intomainfsprojects/FSharp.Control.TaskSeq:mainfrom

repo-assist/test-perf-improve-2026-03-0c358a89d8e70d4cfsprojects/FSharp.Control.TaskSeq:repo-assist/test-perf-improve-2026-03-0c358a89d8e70d4cCopy head branch name to clipboard