public void testPutAfterHash() {
    Hasher hasher = Hashing.hmacMd5(MD5_KEY).newHasher();

    assertEquals(
        "9753980fe94daa8ecaa82216519393a9",
        hasher.putString("The quick brown fox jumps over the lazy dog", UTF_8).hash().toString());
    assertThrows(IllegalStateException.class, () -> hasher.putInt(42));
  }

  public void testHashTwice() {
    Hasher hasher = Hashing.hmacMd5(MD5_KEY).newHasher();

    return stringWriter.toString();
  }

  /**
   * Returns the stack trace of {@code throwable}, possibly providing slower iteration over the full
   * trace but faster iteration over parts of the trace. Here, "slower" and "faster" are defined in
   * comparison to the normal way to access the stack trace, {@link Throwable#getStackTrace()

    return stringWriter.toString();
  }

  /**
   * Returns the stack trace of {@code throwable}, possibly providing slower iteration over the full
   * trace but faster iteration over parts of the trace. Here, "slower" and "faster" are defined in
   * comparison to the normal way to access the stack trace, {@link Throwable#getStackTrace()

            function.bits(),
            function);
      }
    }

    @Override
    HashCode makeHash(Hasher[] hashers) {
      byte[] bytes = new byte[bits() / 8];
      int i = 0;
      for (Hasher hasher : hashers) {
        HashCode newHash = hasher.hash();
        i += newHash.writeBytesTo(bytes, i, newHash.bits() / 8);
      }
      return HashCode.fromBytesNoCopy(bytes);
    }

 *
 * <p>The primary way to provide the data that your hash function should act on is via a {@link
 * Hasher}. Obtain a new hasher from the hash function using {@link #newHasher}, "push" the relevant
 * data into it using methods like {@link Hasher#putBytes(byte[])}, and finally ask for the {@code
 * HashCode} when finished using {@link Hasher#hash}. (See an {@linkplain #newHasher example} of
 * this.)
 *

   * element in the underlying collection and determine which elements satisfy the filter. When a
   * live view is <i>not</i> needed, it may be faster to copy {@code Iterables.filter(unfiltered,
   * predicate)} and use the copy.
   *
   * <p><b>Warning:</b> {@code predicate} must be <i>consistent with equals</i>, as documented at

    Optional<String> optionalName = Optional.fromNullable("bob");
    assertEquals("bob", optionalName.get());
  }

  public void testFromNullable_null() {
    // not promised by spec, but easier to test
    assertSame(Optional.absent(), Optional.fromNullable(null));
  }

  public void testIsPresent_no() {
    assertFalse(Optional.absent().isPresent());
  }

 *
 * @author Louis Wasserman
 * @since 11.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class LongMath {
  // NOTE: Whenever both tests are cheap and functional, it's faster to use &, | instead of &&, ||

  @VisibleForTesting static final long MAX_SIGNED_POWER_OF_TWO = 1L << (Long.SIZE - 2);

  /**
   * Returns the smallest power of two greater than or equal to {@code x}. This is equivalent to

 *       <i>removing</i> that key from the multimap.
 *   <li>The total entry count is available as {@link #size}.
 *   <li>Many complex operations become easier; for example, {@code
 *       Collections.min(multimap.values())} finds the smallest value across all keys.
 * </ul>
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableListMultimap}

 * }</pre>
 *
 * <h3>Alternatives</h3>
 *
 * <h4>Frameworks</h4>
 *
 * <p>When chaining together a graph of asynchronous operations, you will often find it easier to
 * use a framework. Frameworks automate the process, often adding features like monitoring,
 * debugging, and cancellation. Examples of frameworks include:
 *
 * <ul>