Hasher sha1 = Hashing.sha1().newHasher();

    assertEquals(
        "2fd4e1c67a2d28fced849ee1bb76e7391b93eb12",
        sha1.putString("The quick brown fox jumps over the lazy dog", UTF_8).hash().toString());
    assertThrows(IllegalStateException.class, () -> sha1.putInt(42));
  }

  public void testHashTwice() {
    Hasher sha1 = Hashing.sha1().newHasher();

    assertEquals(

      }
    },
    HASH_FUNCTION_VIA_HASHER() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().newHasher().putBytes(input).hash().asBytes();
      }
    };
    ;

    public abstract byte[] hash(Algorithm algorithm, byte[] input);
  }

  private enum Algorithm {
    MD5("MD5", Hashing.md5()),

      }
    },
    HASH_FUNCTION_VIA_HASHER() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().newHasher().putBytes(input).hash().asBytes();
      }
    };
    ;

    public abstract byte[] hash(Algorithm algorithm, byte[] input);
  }

  private enum Algorithm {
    MD5("MD5", Hashing.md5()),

    this.bits = bits;
    this.toString = checkNotNull(toString);
  }

  @Override
  public int bits() {
    return bits;
  }

  @Override
  public Hasher newHasher() {
    return new ChecksumHasher(checksumSupplier.get());
  }

  @Override
  public String toString() {
    return toString;
  }

  /** Hasher that updates a checksum. */

  // MultiplexingOutputStream).
  public HashingOutputStream(HashFunction hashFunction, OutputStream out) {
    super(checkNotNull(out));
    this.hasher = checkNotNull(hashFunction.newHasher());
  }

  @Override
  public void write(int b) throws IOException {
    hasher.putByte((byte) b);
    out.write(b);
  }

  @Override

    this.c = c;
    this.d = d;
    this.k0 = k0;
    this.k1 = k1;
  }

  @Override
  public int bits() {
    return 64;
  }

  @Override
  public Hasher newHasher() {
    return new SipHasher(c, d, k0, k1);
  }

  // TODO(kak): Implement and benchmark the hashFoo() shortcuts.

  @Override
  public String toString() {

    } catch (NoSuchAlgorithmException e) {
      throw new IllegalStateException(e);
    } catch (InvalidKeyException e) {
      throw new IllegalArgumentException(e);
    }
  }

  @Override
  public Hasher newHasher() {
    if (supportsClone) {
      try {
        return new MacHasher((Mac) prototype.clone());
      } catch (CloneNotSupportedException e) {
        // falls through
      }
    }

    try {
      return MessageDigest.getInstance(algorithmName);
    } catch (NoSuchAlgorithmException e) {
      throw new AssertionError(e);
    }
  }

  @Override
  public Hasher newHasher() {
    if (supportsClone) {
      try {
        return new MessageDigestHasher((MessageDigest) prototype.clone(), bytes);
      } catch (CloneNotSupportedException e) {
        // falls through
      }
    }

    try {
      return MessageDigest.getInstance(algorithmName);
    } catch (NoSuchAlgorithmException e) {
      throw new AssertionError(e);
    }
  }

  @Override
  public Hasher newHasher() {
    if (supportsClone) {
      try {
        return new MessageDigestHasher((MessageDigest) prototype.clone(), bytes);
      } catch (CloneNotSupportedException e) {
        // falls through
      }
    }

          // passes, and there is still a little endianness bug lurking around.
        }
      }

      Control control = new Control();
      Hasher controlSink = control.newHasher(1024);

      Iterable<Hasher> sinksAndControl =
          Iterables.concat(sinks, Collections.singleton(controlSink));
      for (int insertion = 0; insertion < totalInsertions; insertion++) {