`.asset_service.Feed`
Required. The new values of feed details. It must match an
existing feed and the field ``name`` must be in the format
of: projects/project_number/feeds/feed_id or
folders/folder_number/feeds/feed_id or
organizations/organization_number/feeds/feed_id.
update_mask
`.field_mask.FieldMask`
Required. Only updates the ``feed`` fields indicated by this
mask. The field mask must not be empty, and it must not
contain fields that are immutable or only set by the server.