final Multiset<E> contents;

    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link
     * ImmutableMultiset#builder}.
     */
    public Builder() {
      this(LinkedHashMultiset.<E>create());
    }

    Builder(Multiset<E> contents) {
      this.contents = contents;
    }

    /**

      return this;
    }

    /**
     * Returns a newly-created {@code ImmutableSortedMultiset} based on the contents of the {@code
     * Builder}.
     */
    @Override
    public ImmutableSortedMultiset<E> build() {
      return copyOfSorted((SortedMultiset<E>) contents);
    }
  }

  @J2ktIncompatible // serialization
  private static final class SerializedForm<E> implements Serializable {

import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.stream.Collector;
import javax.annotation.CheckForNull;

/**
 * A {@link RangeSet} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * @author Louis Wasserman
 * @since 14.0
 */

import java.util.function.Function;
import java.util.stream.Collector;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link RangeMap} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * @author Louis Wasserman
 * @since 14.0
 */
@GwtIncompatible // NavigableMap
@ElementTypesAreNonnullByDefault

import java.util.function.Consumer;
import java.util.stream.Collector;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link Set} whose contents will never change, with many other important properties detailed at
 * {@link ImmutableCollection}.
 *
 * @since 2.0
 */
@GwtCompatible(serializable = true, emulated = true)

   * PermittedMetaException}.
   */
  protected final class MultiExceptionListIterator implements ListIterator<E> {
    // TODO: track seen elements when order isn't guaranteed
    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**

  }

  /**
   * Converts an iterable into a collection. If the iterable is already a collection, it is
   * returned. Otherwise, an {@link java.util.ArrayList} is created with the contents of the
   * iterable in the same iteration order.
   */
  private static <E extends @Nullable Object> Collection<E> castOrCopyToCollection(
      Iterable<E> iterable) {
    return (iterable instanceof Collection)

   *
   * <p>A collection is considered immutable if:
   *
   * <ol>
   *   <li>All its mutation methods result in UnsupportedOperationException, and do not change the
   *       underlying contents.
   *   <li>All methods that return objects that can indirectly mutate the collection throw
   *       UnsupportedOperationException when those mutators are called.
   * </ol>
   *

    Comparable<?>[] contents = new Comparable<?>[6 + remaining.length];
    contents[0] = e1;
    contents[1] = e2;
    contents[2] = e3;
    contents[3] = e4;
    contents[4] = e5;
    contents[5] = e6;
    System.arraycopy(remaining, 0, contents, 6, remaining.length);
    return construct(Ordering.natural(), contents.length, (E[]) contents);
  }

   * ImmutableSortedSet) creates an empty sortedDelegate, which, in a vacuum, sets this object's
   * contents to empty. By contrast, the non-GWT constructor with the same signature uses the
   * comparator only as a comparator. It does NOT assume empty contents. (It requires an
   * implementation of iterator() to define its contents, and methods like contains() are