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

/**
 * A {@link NavigableSet} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * <p><b>Warning:</b> as with any sorted collection, you are strongly advised not to use a {@link

      checkNotNull(element);
      copyIfNecessary();
      if (n == elements.length) {
        sortAndDedup();
        /*
         * Sorting operations can only be allowed to occur once every O(n) operations to keep
         * amortized O(n log n) performance.  Therefore, ensure there are at least O(n) *unused*
         * spaces in the builder array.
         */

  public <T extends @Nullable Object> T[] toArray(T[] other) {
    return ObjectArrays.toArrayImpl(this, other);
  }

  @Override
  public boolean contains(@Nullable Object object) {
    try {
      // This set never contains null.  We need to explicitly check here
      // because some comparator might throw NPE (e.g. the natural ordering).
      return object != null && sortedDelegate.contains(object);
    } catch (ClassCastException e) {