feat: support File.OpenHandle and RandomAccess in MockFileSystem - #1546

Queue entry conditions

• any of [🔀 queue conditions]:
  • all of [📌 queue conditions of queue rule default]:
    • #review-threads-unresolved = 0 [🛡 GitHub repository ruleset rule main]
    • any of [🛡 GitHub repository ruleset rule main]:
      • check-neutral = @github-actions/Unit tests (macos-latest)
      • check-skipped = @github-actions/Unit tests (macos-latest)
      • check-success = @github-actions/Unit tests (macos-latest)
    • any of [🛡 GitHub repository ruleset rule main]:
      • check-neutral = @github-actions/Unit tests (ubuntu-latest)
      • check-skipped = @github-actions/Unit tests (ubuntu-latest)
      • check-success = @github-actions/Unit tests (ubuntu-latest)
    • any of [🛡 GitHub repository ruleset rule main]:
      • check-neutral = @github-actions/Unit tests (windows-latest)
      • check-skipped = @github-actions/Unit tests (windows-latest)
      • check-success = @github-actions/Unit tests (windows-latest)
    • any of [🛡 GitHub repository ruleset rule main]:
      • check-neutral = @github-actions/API tests
      • check-skipped = @github-actions/API tests
      • check-success = @github-actions/API tests
    • github-review-approved [🛡 GitHub repository ruleset rule main]
    • any of [🛡 GitHub repository ruleset rule main]:
      • check-success = Testably/Conventional-Commits
      • check-neutral = Testably/Conventional-Commits
      • check-skipped = Testably/Conventional-Commits
• -closed [📌 queue requirement]
• -conflict [📌 queue requirement]
• -draft [📌 queue requirement]
• any of [📌 queue -> configuration change requirements]:
  • -mergify-configuration-changed
  • check-success = @mergify/Configuration changed
  • check-success = @mergify/Configuration has been deleted

You can queue this pull request now with @Mergifyio queue: it will enter the merge queue once these conditions match.