@Override
        public long getDateHeader(String name) {
            return -1;
        }

        @Override
        public Enumeration<String> getHeaders(String name) {
            return null;
        }

        @Override
        public Enumeration<String> getHeaderNames() {
            return null;
        }

        @Override
        public int getIntHeader(String name) {

        public long getDateHeader(String name) {
            return -1;
        }

        @Override
        public java.util.Enumeration<String> getHeaders(String name) {
            return java.util.Collections.emptyEnumeration();
        }

        @Override
        public java.util.Enumeration<String> getHeaderNames() {
            return java.util.Collections.emptyEnumeration();
        }

        @Override

      Enumeration<T> enumeration) {
    checkNotNull(enumeration);
    return new UnmodifiableIterator<T>() {
      @Override
      public boolean hasNext() {
        return enumeration.hasMoreElements();
      }

      @Override
      @ParametricNullness
      public T next() {
        return enumeration.nextElement();
      }
    };
  }

import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Base64;
import java.util.Calendar;
import java.util.Date;
import java.util.Enumeration;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.regex.Matcher;

                return null;
            }

            @Override
            public java.util.Enumeration<String> getHeaders(String name) {
                return null;
            }

            @Override
            public java.util.Enumeration<String> getHeaderNames() {
                return null;
            }

            @Override

                return null;
            }

            @Override
            public java.util.Enumeration<String> getHeaders(String name) {
                return null;
            }

            @Override
            public java.util.Enumeration<String> getHeaderNames() {
                return null;
            }

            @Override

        public String getHeader(String name) {
            return null;
        }

        @Override
        public java.util.Enumeration<String> getHeaders(String name) {
            return java.util.Collections.emptyEnumeration();
        }

        @Override
        public java.util.Enumeration<String> getHeaderNames() {
            return java.util.Collections.emptyEnumeration();
        }

        @Override

    Enumeration<Integer> enumer = Iterators.asEnumeration(iter);

    assertFalse(enumer.hasMoreElements());
    assertThrows(NoSuchElementException.class, () -> enumer.nextElement());
  }

  public void testAsEnumerationSingleton() {
    Iterator<Integer> iter = ImmutableList.of(1).iterator();
    Enumeration<Integer> enumer = Iterators.asEnumeration(iter);

            throw new UnsupportedOperationException();
        }

        @Override
        public java.util.Enumeration<String> getHeaders(String name) {
            throw new UnsupportedOperationException();
        }

        @Override
        public java.util.Enumeration<String> getHeaderNames() {
            throw new UnsupportedOperationException();
        }

        @Override

    Enumeration<Integer> enumer = Iterators.asEnumeration(iter);

    assertFalse(enumer.hasMoreElements());
    assertThrows(NoSuchElementException.class, () -> enumer.nextElement());
  }

  public void testAsEnumerationSingleton() {
    Iterator<Integer> iter = ImmutableList.of(1).iterator();
    Enumeration<Integer> enumer = Iterators.asEnumeration(iter);