How John Sped Up His Code by Switching from ImmutableList and ImmutableDictionary to ImmutableArray and FrozenDictionary

Legendary C# developer John Skett explained how the move to lighter, more powerful immutable collections — ImmutableArray and FrozenDictionary — unexpectedly gave a major speed boost to his 2029 election simulation project. Although the migration required only minimal edits, key operations such as election context validation were sped up by almost seven times, confirming that the right choice of data structures is critical even in already optimized systems