Class AsyncConditionTransfer<T>

Transfer with asynchronous conditional filtering on input and output.

Capabilities: isInput, isOutput, isDuplex, isAsyncPushable, isSubscribable

Mechanics:

1. shouldAccept(data) — async input filter (if false, data is ignored)
2. shouldEmit(data) — async output filter (if false, data is not emitted)
3. asyncPush(data) — await shouldAccept → await shouldEmit → sendState + clear
4. Predicates can be sync or async (return Promise | boolean)

Sequence Guard (active when maxConcurrency > 1):

• Multiple shouldAccept/shouldEmit checks run in parallel (up to maxConcurrency).
• Emissions to subscribers happen strictly in data-arrival order.
• shouldEmit receives the operation's local data, not a shared _state.value, so it cannot accidentally inspect another operation's data.
• When maxConcurrency <= 1, the guard is inactive (no overhead).

Error handling:

• If shouldAccept throws an exception, onAcceptError is called.
• If shouldEmit throws an exception, onEmitError is called.
• With the corresponding handler provided, the exception is suppressed.
• When the guard is active, a failed/skipped operation submits a no-emit marker to the queue so that subsequent results are not blocked.

Configuration (AsyncConditionTransferConfig):

• shouldAccept?: (data: T) => Promise | boolean
• shouldEmit?: (data: T) => Promise | boolean
• onAcceptError?: ErrorHandler
• onEmitError?: ErrorHandler
• maxConcurrency?, bufferSize?, onBufferOverflow? (BackpressureConfig)