gather icat metadata in independent greenlets
currently there are loops in https://gitlab.esrf.fr/bliss/bliss/-/blob/master/bliss/controllers/icatmeta.py#L27 that potentially involve hardware communication.
def get_metadata(self):
...
for key, value in self.mapping.items():
...
for key, device in self.objects.items():
...
It would be better to spawn a set of tasks greenlets to make this whole process faster.
To do so one would need to play with the config object to make sure one spawns the greenlets before the "$." references are evaluated. ... @matias.guijarro had some ideas/input for that but I don't find them any more...