How to prefetch only the primary keys for a Many to Many Relation?

class Team(Model):
    id = fields.IntField(pk=True)
    events: fields.ManyToManyRelation[Event]

class Event(Model):
    id = fields.IntField(pk=True)
    participants = fields.ManyToManyField('models.Team', related_name='events', through='event_team')

How do I correctly prefetch so I can access the primary keys of the ManyToMany relation?
I have models with binary blobs and I'd like to only return the related IDs over an API.

I expected this to work but unfortunately it doesn't

t = await Team.get(pk=1).first().prefetch_related('events__id'')

# I'd like to just have the PKs of the relations
for event_id in t.events__id:
    print(event_id)

Start with the prefetch_related entry point and the ManyToMany relation-loading documentation. Determine whether related primary keys can be prefetched without loading binary fields, and document the supported usage or limitation for accessing those IDs.