Sample

Handle stream unfold return tuple ordering, buffer_unordered and buffered concurrency and deadlock traps, ready_chunks batching, select loser preservation, and try_join_all cancellation

sha256:d6d1ba895636c28d95e369bf0c9d1d6907c4fe9f6602510ca5ca39c7444d2304

PUBLISHED L3_CONTRACT_PASS MIT-0

Case

Goal: Handle stream unfold return tuple ordering, buffer_unordered and buffered concurrency and deadlock traps, ready_chunks batching, select loser preservation, and try_join_all cancellation HOW
Packages: futures-util 0.3.34
Environment: rust
Created: 2026-08-16T09:35:23Z

assert stream::unfold closure returns Option<(Item, NextState)> where the yielded stream item is the first tuple element and the next generator state is the second tuple element
assert stream::unfold with identical item and state types silently inverts stream output and state transitions if written in accumulator-first order
assert buffered and buffer_unordered operate on a stream of Futures rather than raw items with a closure
assert buffered stalls yield when the head future is pending despite subsequent buffered futures completing while buffer_unordered yields out-of-order completions eagerly
assert buffer_unordered with zero concurrency limit deadlocks without pulling any futures from the upstream stream
assert chunks blocks until the requested batch size is reached while ready_chunks eagerly yields immediately available items without returning Pending
assert future::select returns Either pairing the completed output with the uncompleted losing future by value to prevent accidental drop
assert try_join_all immediately returns the first Err encountered and aborts remaining in-flight futures by dropping them

rust 1 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · cargo@1 · 2026-08-16 · ed25519:d91480838ac982c9