bufferAsyncFrames
Buffers a flow of AsyncFrame and closes every frame the collector does not receive. It is the suspending form of bufferFrames, which cannot serve here: the close of an AsyncFrame waits for the runtime's lane, and a channel's own hook for a dropped element cannot wait.
A frame reaches the collector when the collector's emit is called with it, even when that call then throws. The collector closes those frames. When the collection ends, this operator stops the upstream, closes every frame that is still buffered, and only then completes.
Parameters
Channel.BUFFERED, or a count of zero or more, where zero hands each frame over directly. Channel.UNLIMITED, Channel.CONFLATED and every other negative value are refused.
where the upstream runs, as flowOn would place it. The codec work itself stays in the runtime's lane.