fun peek(): Headers? = null

  @Throws(IOException::class)
  fun get(): Headers

  companion object {
    @JvmField
    val EMPTY: TrailersSource =
      object : TrailersSource {
        override fun peek() = Headers.EMPTY

        override fun get() = Headers.EMPTY
      }
  }

    return CollectCollectors.toImmutableRangeSet();
  }

  /**
   * Returns an empty immutable range set.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked")
  public static <C extends Comparable> ImmutableRangeSet<C> of() {
    return (ImmutableRangeSet<C>) EMPTY;
  }

  /**

import java.util.Set;
import java.util.concurrent.ExecutionException;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * {@link LoadingCache} tests that deal with empty caches.
 *
 * @author mike nonemacher
 */

@NullUnmarked
public class EmptyCachesTest extends TestCase {

  public void testEmpty() {
    for (LoadingCache<Object, Object> cache : caches()) {

                return OptionalEntity.empty();
            }
        }, WebConfigService.class.getCanonicalName());

        assertTrue(crawlingConfigHelper.getPipeline("W1").isEmpty());
    }

    public void test_getPipeline_withEmptyStringPipeline() {
        // Register service that returns empty string pipeline
        ComponentUtil.register(new WebConfigService() {

        // Test with another type and empty raw data
        int type2 = AvPair.MsvAvEOL;
        byte[] raw2 = new byte[] {};
        AvPair avPair2 = new AvPair(type2, raw2);

        assertEquals(type2, avPair2.getType(), "Type should match the constructor argument for empty raw data.");
        assertArrayEquals(raw2, avPair2.getRaw(), "Raw data should match the constructor argument for empty raw data.");

        // Test with null raw data

    }

    @Test
    @DisplayName("mechanism token empty array – preserved after round‑trip")
    void testEmptyMechanismToken() throws IOException {
        NegTokenTarg nt = new NegTokenTarg();
        nt.setResult(NegTokenTarg.REQUEST_MIC);
        nt.setMechanismToken(new byte[0]); // empty but non‑null
        nt.setMechanism(new ASN1ObjectIdentifier("2.16.840.1.101.3.6.1"));

  }

  public static <E extends Enum<E>> EnumMultiset<E> create(Iterable<E> elements) {
    Iterator<E> iterator = elements.iterator();
    checkArgument(iterator.hasNext(), "EnumMultiset constructor passed empty Iterable");
    EnumMap<E, Count> map = new EnumMap<>(getDeclaringClassOrObjectForJ2cl(iterator.next()));
    EnumMultiset<E> multiset = new EnumMultiset<>(map);
    Iterables.addAll(multiset, elements);
    return multiset;

    //                                  --------------------
    /**
     * Set the value of hostname, used in parameter comment. <br>
     * Even if empty string, treated as empty plainly. So "IF pmb != null" is false if empty.
     * @param hostname The parameter value of hostname. (NotNull)
     */
    public void setHostname(String hostname) {
        registerVariable("hostname", hostname);
    }

        List<KerberosAuthData> result = KerberosAuthData.parse(unknownAuthType, emptyToken, mockKeys);

        // THEN the result should be an empty list
        assertNotNull(result, "The result should not be null.");
        assertTrue(result.isEmpty(), "The result should be empty for unknown auth types.");
    }

    /**
     * Test parsing of {@link KerberosConstants#AUTH_DATA_PAC} with an invalid token.

				href="#searchOptions" class="badge text-bg-primary text-decoration-none"
				data-bs-toggle="collapse"> <c:if test="${empty lang}">
						<la:message key="labels.searchoptions_all" />
					</c:if> <c:if test="${!empty lang}">
						<c:forEach var="sLang" items="${lang}">
							<c:forEach var="item" items="${langItems}">
								<c:if test="${item.value==sLang}">${f:h(item.label)}</c:if>