rxdart: Get buffered elements on stream subscription cancel

Question

I'm using a rxdart ZipStream within my app to combine two streams of incoming bluetooth data. Those streams are used along with "bufferCount" to collect 500 elements each before emitting. Everything works fine so far, but if the stream subscription gets cancelled at some point, there might be a number of elements in those buffers that are omitted after that. I could wait for a "buffer cycle" to complete before cancelling the stream subscription, but as this might take some time depending on the configured sample rate, I wonder if there is a solution to get those buffers as they are even if the number of elements might be less than 500.

Here is some simplified code for explanation:

subscription = ZipStream.zip2(
  streamA.bufferCount(500),
  streamB.bufferCount(500),
  (streamABuffer, streamBBuffer) {
    return ...;
  },
).listen((data) {
  ...
});

Thanks in advance!