fixed #686 - make channel confirmations truly async - #723
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Eugeny
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June 6, 2026 19:38
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Before Eugeny#723, synchronous channel acceptance/rejection would happen regardless of message dispatch. Now, the channel reply uses the same bounded mpsc channel that the handler consumes from. However, under contention (for example, with multiple simultaneous channels opening and writing over the same handler), the awaits in `ChannelOpenHandleInner::accept` and `ChannelOpenHandleInner::reject` may hang while the consumer is the handler itself, thus leading to a self-deadlock. This PR changes channel confirmation to use its own unbounded channel on both server and client implementations, avoiding any awaits (since send is sync), and thus, any deadlocks under load. Because of the change to `ChannelOpenHandleInner::accept` and `ChannelOpenHandleInner::reject` into sync methods, this is backwards-incompatible.
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