||A filter that uses a custom callback to determine which fields should be
accepted. Your callback will be given be called one time for each field,
with a field passed as the first argument to your callback each time. If
you return true, the field will be included. Otherwise, it will not.
||Filter a set of fields into a \Dewdrop\Fields\GroupedFields object.
||This filter will allow certain fields, which would otherwise be visible
based upon their actual definition/permissions, to be excluded in certain
contexts. The most common use of this filter is to allow a user to select
which particular columns they'd like to be visible in a listing table.