long topSize) {
    checkArgument(
        (topCharacteristics & Spliterator.SUBSIZED) == 0,
        "flatMap does not support SUBSIZED characteristic");
    checkArgument(
        (topCharacteristics & Spliterator.SORTED) == 0,
        "flatMap does not support SORTED characteristic");
    checkNotNull(fromSpliterator);
    checkNotNull(function);
    return new FlatMapSpliteratorOfObject<>(

      }
    }
  }

  /**
   * Test for 2-bit characteristics. A characteristic is a delta in the input which is repeated in
   * the output. For example, if f() is a block cipher and c is a characteristic, then f(x^c) =
   * f(x)^c with greater than expected probability. The test for funneling is merely a test for
   * 1-bit characteristics.
   *

      }
    }
  }

  /**
   * Test for 2-bit characteristics. A characteristic is a delta in the input which is repeated in
   * the output. For example, if f() is a block cipher and c is a characteristic, then f(x^c) =
   * f(x)^c with greater than expected probability. The test for funneling is merely a test for
   * 1-bit characteristics.
   *

 *       always returns zero could be called a hash function. It is not.)
 * </ul>
 *
 * <p>Summarizing the last two points: "equal yield equal <i>always</i>; unequal yield unequal
 * <i>often</i>." This is the most important characteristic of all hash functions.
 *
 * <h3>Desirable properties</h3>
 *
 * <p>A high-quality hash function strives for some subset of the following virtues:
 *
 * <ul>

    abstract boolean tryAdvance(Consumer<? super E> action);

    abstract @Nullable GeneralSpliterator<E> trySplit();

    final int characteristics() {
      return spliterator.characteristics();
    }

    final long estimateSize() {
      return spliterator.estimateSize();
    }

    final Comparator<? super E> getComparator() {
      return spliterator.getComparator();

// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This file encapsulates some of the odd characteristics of the RISCV64
// instruction set, to minimize its interaction with the core of the
// assembler.

package arch

import (
	"cmd/internal/obj"
	"cmd/internal/obj/riscv"
)

  public final CollectorTester<T, A, R> expectCollects(R expectedResult, T... inputs) {
    List<T> list = Arrays.asList(inputs);
    doExpectCollects(expectedResult, list);
    if (collector.characteristics().contains(Collector.Characteristics.UNORDERED)) {
      Collections.reverse(list);
      doExpectCollects(expectedResult, list);
    }
    return this;
  }

    return Collector.of(
        EnumSetAccumulator::new,
        EnumSetAccumulator::add,
        EnumSetAccumulator::combine,
        EnumSetAccumulator::toImmutableSet,
        Collector.Characteristics.UNORDERED);
  }

  private static final class EnumSetAccumulator<E extends Enum<E>> {
    @SuppressWarnings({"rawtypes", "unchecked"})

      Collector.of(
          ToOptionalState::new,
          ToOptionalState::add,
          ToOptionalState::combine,
          ToOptionalState::getOptional,
          Collector.Characteristics.UNORDERED);

  /**
   * A collector that converts a stream of zero or one elements to an {@code Optional}.
   *
   * @throws IllegalArgumentException if the stream consists of two or more elements.

    return Collector.of(
        EnumSetAccumulator::new,
        EnumSetAccumulator::add,
        EnumSetAccumulator::combine,
        EnumSetAccumulator::toImmutableSet,
        Collector.Characteristics.UNORDERED);
  }

  @IgnoreJRERequirement // see enclosing class (whose annotation Animal Sniffer ignores here...)
  private static final class EnumSetAccumulator<E extends Enum<E>> {