return insertionOrder;
  }

  /**
   * Compares strings in natural order except that null comes immediately before a given value. This
   * works better than Ordering.natural().nullsFirst() because, if null comes before all other
   * values, it lies outside the submap/submultiset ranges we test, and the variety of tests that
   * exercise null handling fail on those subcollections.
   */

      return buildOrThrow();
    }

    private ImmutableMap<K, V> build(boolean throwIfDuplicateKeys) {
      if (valueComparator != null) {
        Collections.sort(
            entries, Ordering.from(valueComparator).onResultOf(Maps.<V>valueFunction()));
      }
      return fromEntryList(throwIfDuplicateKeys, entries);
    }

    public ImmutableMap<K, V> buildOrThrow() {

                if (result < 0 || (result == 0 && (!lowerBoundInclusive || !upperBoundInclusive))) {
                    throw new InvalidVersionSpecificationException("Range defies version ordering: " + spec);
                }
            }

            restriction = new Restriction(lowerVersion, lowerBoundInclusive, upperVersion, upperBoundInclusive);
        }

        return restriction;
    }

   * iterables are equivalent to one another.
   *
   * <p>Note that this method performs a similar function for equivalences as {@link
   * com.google.common.collect.Ordering#lexicographical} does for orderings.
   *
   * <p>The returned object is serializable if this object is serializable.
   *
   * @since 10.0
   */
  public final <S extends @Nullable T> Equivalence<Iterable<S>> pairwise() {

 * invoke methods, they invoke methods on the {@code ForwardingNavigableMap}.
 *
 * <p>Each of the {@code standard} methods uses the map's comparator (or the natural ordering of the
 * elements, if there is no comparator) to test element equality. As a result, if the comparator is
 * not consistent with equals, some of the standard implementations may violate the {@code Map}
 * contract.
 *

 * invoke methods, they invoke methods on the {@code ForwardingNavigableMap}.
 *
 * <p>Each of the {@code standard} methods uses the map's comparator (or the natural ordering of the
 * elements, if there is no comparator) to test element equality. As a result, if the comparator is
 * not consistent with equals, some of the standard implementations may violate the {@code Map}
 * contract.
 *

 * average, in the marking phase, not {@code 5.0} as in {@code java.util.HashSet}.
 *
 * <p>If there are no removals, then {@link #iterator iteration} order is the same as insertion
 * order. Any removal invalidates any ordering guarantees.
 *
 * <p>This class should not be assumed to be universally superior to {@code java.util.HashSet}.
 * Generally speaking, this class reduces object allocation and memory consumption at the price of

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.Iterables;
import com.google.common.collect.Multiset;
import com.google.common.collect.Ordering;
import com.google.common.primitives.Chars;
import org.jspecify.annotations.NullUnmarked;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.Iterables;
import com.google.common.collect.Multiset;
import com.google.common.collect.Ordering;
import com.google.common.primitives.Chars;
import org.jspecify.annotations.NullUnmarked;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)

     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can
     * return the same element. This enables the assertion to pass and the reference iterator to