public String formatProgress(long progressedSize, long size) {
            if (progressedSize < 0L) {
                throw new IllegalArgumentException("progressed file size cannot be negative: " + progressedSize);
            }
            if (size >= 0L && progressedSize > size) {
                throw new IllegalArgumentException(
                        "progressed file size cannot be greater than size: " + progressedSize + " > " + size);

    @Override
    public boolean hasNext() {
      return true; // pretend that you have more...
    }

    @Override
    public E next() {
      // ...but throw an unchecked exception when you ask for it.
      if (!iterator.hasNext()) {
        throw new ThrowsAtEndException();
      }
      return iterator.next();
    }

    @Override
    public void remove() {
      iterator.remove();
    }
  }

            getMap()
                .compute(
                    k0(),
                    (k, v) -> {
                      assertEquals(k0(), k);
                      assertEquals(v0(), v);
                      throw new SomeUncheckedException();
                    }));
    expectUnchanged();
  }

  @MapFeature.Require({SUPPORTS_PUT, SUPPORTS_REMOVE})
  public void testCompute_absentFunctionThrows() {
    assertThrows(

      @Override
      public V load(K key) {
        throw e;
      }
    };
  }

  /** Returns a {@link CacheLoader} that throws the given exception for every request. */
  static <K, V> CacheLoader<K, V> exceptionLoader(Exception e) {
    checkNotNull(e);
    return new CacheLoader<K, V>() {
      @Override
      public V load(K key) throws Exception {
        throw e;
      }
    };
  }

    bufferHelper(
        "\nempty first line\nno newline at end", "\n", "empty first line\n", "no newline at end");
    bufferHelper("three\rlines\rno newline at end", "three\r", "lines\r", "no newline at end");
    bufferHelper("mixed\nline\rendings\r\n", "mixed\n", "line\r", "endings\r\n");
  }

  private static final ImmutableSet<Integer> CHUNK_SIZES =

            getMap()
                .compute(
                    k0(),
                    (k, v) -> {
                      assertEquals(k0(), k);
                      assertEquals(v0(), v);
                      throw new SomeUncheckedException();
                    }));
    expectUnchanged();
  }

  @MapFeature.Require({SUPPORTS_PUT, SUPPORTS_REMOVE})
  public void testCompute_absentFunctionThrows() {
    assertThrows(

    bufferHelper(
        "\nempty first line\nno newline at end", "\n", "empty first line\n", "no newline at end");
    bufferHelper("three\rlines\rno newline at end", "three\r", "lines\r", "no newline at end");
    bufferHelper("mixed\nline\rendings\r\n", "mixed\n", "line\r", "endings\r\n");
  }

  private static final ImmutableSet<Integer> CHUNK_SIZES =

  public K firstKey() {
    Entry<K, V> entry = firstEntry();
    if (entry == null) {
      throw new NoSuchElementException();
    } else {
      return entry.getKey();
    }
  }

  @Override
  @ParametricNullness
  public K lastKey() {
    Entry<K, V> entry = lastEntry();
    if (entry == null) {
      throw new NoSuchElementException();
    } else {
      return entry.getKey();
    }
  }

      throw new UnsupportedOperationException();
    }

    @Override
    public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
      throw new UnsupportedOperationException();
    }

    @Override
    public @Nullable V putIfAbsent(K key, V value) {
      throw new UnsupportedOperationException();
    }

    @Override

    public Object badIgnored() {
      return new BadEquals();
    }

    // primitive ignored
    public int returnsInt() {
      throw new UnsupportedOperationException();
    }

    // void ignored
    public void voidMethod() {
      throw new UnsupportedOperationException();
    }

    // non-public method ignored
    static Object badButNotPublic() {
      return new BadEquals();
    }
  }