Every now and then I cannot save my epochs objects due to this error.
This happens only for one of my subjects (out of thirty) and only on one
particular (bandpass filtered and hilbert transformed) raw file. I have
tried both the development version and newest stable version.
I guess it should take care of it automatically as I didn't change the
default split size of 2GB of epochs_hilbert.save()
I suspect I understand why this can happen from the code -- we calculate
the splits using just the size of the actual data, but end up writing that
plus other things (drop log, metadata, etc.) which can push it beyond the
2GB limit. For now you can do something like `split_size='1.9GB'` to work
around the problem, but hopefully we can cook up a proper fix for it soon.
