either function
Creates a composite filter which groups one or more field filters with the EITHER
operator.
At least one field filter should pass in order for the composite filter to pass.
Implementation
Composite either(Iterable<SimpleFilter> filters) {
return Composite._(CompositeFilter()
..operator = CompositeFilter_CompositeOperator.EITHER
..filter.addAll(filters.map((f) => f.filter))
..freeze());
}