In the streaming example of the README: ```python from BeatNet.BeatNet import BeatNet estimator = BeatNet(1, mode='stream', inference_model='PF', plot=[], thread=False) Output = estimator.process() ``` It is unclear to me how to process the beats as soon as they are detected, without waiting for `.process()` to return. For example, is it currently possible to use some kind of callback? If so, how?