Dynamic chunking fails if empty

[cfuselli]

Need to check again but I think the dynamic chunking fails with a numba error if the chunk is empty

[WenzDaniel]

Just adding another issue I noticed while reading the code. I think dynamic chunking fails silently if the separation scale is smaller than the event time difference. For example when using a setting like:

        "fixed_event_spacing": True,
        "source_rate": 0.5*10**-9,
        "separation_scale": 0.5*10**8,

[cfuselli]

Thanks @WenzDaniel, right I also noticed it a couple of days ago but did not have time to look at it yet.