We didn’t port the audio buffer nodes yet, but there are two possibilities with a bit of extra work:
Import them in the same way as the other audio signal nodes got imported, they are mostly pretty easy since they create their pins via reflection. You can look at the buffer nodes in beta to see how they are supposed to work.
Patch your own audio buffer with the new regions I’ve just added to the nuget two days ago. There is now an example patch for a stereo audio processor that is patched, you could modify that in a way that it stores samples in a large mutable array and reads them back later…