Method combiner

forge-core/src/main/java/forge/util/ItemPool.java:87–93

()

            }

            @Override
            public BinaryOperator<ItemPool<T>> combiner() {
                return (first, second) -> {
                    first.addAll(second);
                    return first;
                };
            }

            @Override public Function<ItemPool<T>, ItemPool<T>> finisher() {
                return Function.identity();