@Override
public <V, R extends MutableMultimap<V, T>> R groupBy(
Function<? super T, ? extends V> function, R target) {
this.forEach(MultimapPutProcedure.on(target, function));
return target;
}
/** Implemented to avoid megamorphic call on castProcedure */
private void batchGroupBy(int start, int end, MultimapPutProcedure<?, T> castProcedure) {
for (int i = start; i < end; i++) {
castProcedure.value(this.items[i]);
}
}