assertThat(empty).isEmpty();
  }

  public void testCharacterSplitWithTrim() {
    String jacksons = "arfo(Marlon)aorf, (Michael)orfa, afro(Jackie)orfa, ofar(Jemaine), aff(Tito)";
    Iterable<String> family =
        COMMA_SPLITTER
            .trimResults(CharMatcher.anyOf("afro").or(CharMatcher.whitespace()))
            .split(jacksons);
    assertThat(family)

    // Now we hit the cap
    assertEquals(1 << 30, ImmutableSet.chooseTableSize(1 << 29));
    assertEquals(1 << 30, ImmutableSet.chooseTableSize((1 << 30) - 1));

    // Now we've gone too far
    assertThrows(IllegalArgumentException.class, () -> ImmutableSet.chooseTableSize(1 << 30));
  }

  @GwtIncompatible // RegularImmutableSet.table not in emulation
  public void testResizeTable() {

    // Now we hit the cap
    assertEquals(1 << 30, ImmutableSet.chooseTableSize(1 << 29));
    assertEquals(1 << 30, ImmutableSet.chooseTableSize((1 << 30) - 1));

    // Now we've gone too far
    assertThrows(IllegalArgumentException.class, () -> ImmutableSet.chooseTableSize(1 << 30));
  }

  @GwtIncompatible // RegularImmutableSet.table not in emulation
  public void testResizeTable() {

   * range [0, k) and ignore the remaining elements.
   */
  private final @Nullable T[] buffer;
  private int bufferSize;

  /**
   * The largest of the lowest k elements we've seen so far relative to this comparator. If
   * bufferSize ≥ k, then we can ignore any elements greater than this value.
   */
  private @Nullable T threshold;

 * constant time operations. Expected in the hashtable sense (depends on the hash function doing a
 * good job of distributing the elements to the buckets to a distribution not far from uniform), and
 * amortized since some operations can trigger a hash table resize.
 *
 * <p>This implementation consumes significantly less memory than {@code java.util.LinkedHashSet} or

import org.jspecify.annotations.NullUnmarked;

/**
 * Helper classes for various benchmarks.
 *
 * @author Christopher Swenson
 */
@NullUnmarked
final class BenchmarkHelpers {
  /** So far, this is the best way to test various implementations of {@link Set} subclasses. */
  public interface CollectionsImplEnum {
    <E extends Comparable<E>> Collection<E> create(Collection<E> contents);

    String name();
  }

       * Unsafe on modern JVMs (if perhaps not quite as fast as VarHandle?). However, I'm not sure
       * exactly what we've benchmarked, and we certainly haven't benchmarked as far back as JDK 8.
       * (We also haven't benchmarked under Android. We continue to use UnsafeAtomicHelper there so
       * that we don't change the performance there, for better or for worse.) Fortunately, JVM

   * mode}.
   *
   * <p>For the case of {@link RoundingMode#HALF_DOWN}, {@code HALF_UP}, and {@code HALF_EVEN},
   * infinite {@code double} values are considered infinitely far away. For example, 2^2000 is not
   * representable as a double, but {@code roundToDouble(BigInteger.valueOf(2).pow(2000), HALF_UP)}
   * will return {@code Double.MAX_VALUE}, not {@code Double.POSITIVE_INFINITY}.
   *

      /*
       * requireNonNull is safe because:
       *
       * - columnIterator started off pointing to an empty iterator, so we must have entered the
       *   `if` body above at least once. Thus, if we got this far, that `if` body initialized
       *   rowEntry at least once.
       *
       * - The only case in which rowEntry is cleared (during remove() below) happens only if the

    //     imagine a line separating the first block from the second, we can proceed by exchanging
    //     the smaller of these blocks with the far end of the other one. That leaves us with a
    //     smaller version of the same problem.
    //     Say we are rotating abcdefgh by 5. We start with abcde|fgh. The smaller block is [fgh]: