Multi-stream: == on a boxed join key works below 128 and fails above

Integer.valueOf caches -128..127, so identity comparison on a small join key appears to work and keeps working right up to the day an id crosses 127. The bug ships because the test data was small.

• Multi-stream: a record with a mutable component is a broken Map key
• Multi-stream: an unmodifiable view is not a snapshot of the feed
• Multi-stream: toMap's merge function runs only on a collision
• Multi-stream: nothing runs until the terminal operation
• Multi-stream: indexing the other side costs memory a sorted merge does not
• Multi-stream: UNORDERED is a promise you make, not one you receive

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Published 2026-09-20

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