Is there a reason the parameter name for ForwardingMap.remove(Object object) does not match the interface: Map.remove(Object key)?  In short: 'object' != 'key'
If yes, please kindly explain the history.
Else, can we rename to 'key' to match the interface?
assertEquals(Range.closed(3, 5), rangeSet.rangeContaining(5));
    assertTrue(rangeSet.contains(5));
    assertEquals(Range.closed(7, 10), rangeSet.rangeContaining(8));
    assertTrue(rangeSet.contains(8));
    assertNull(rangeSet.rangeContaining(6));
    assertFalse(rangeSet.contains(6));
  }
  public void testAddAll() {
    RangeSet<Integer> rangeSet = TreeRangeSet.create();
    rangeSet.add(Range.closed(3, 10));
    rangeSet.addAll(Arrays.asList(Range.open(1, 3), Range.closed(5, 8), Range.closed(9, 11)));
    assertThat(rangeSet.asRanges()).containsExactly(Range.openClosed(1, 11)).inOrder();
  }
  public void testRemoveAll() {
    RangeSet<Integer> rangeSet = TreeRangeSet.create();
    rangeSet.add(Range.closed(3, 10));
    rangeSet.removeAll(Arrays.asList(Range.open(1, 3), Range.closed(5, 8), Range.closed(9, 11)));
    assertThat(rangeSet.asRanges())
        .containsExactly(Range.closedOpen(3, 5), Range.open(8, 9))
        .inOrder();
  }
  @GwtIncompatible 
  public void testSerialization() {
    RangeSet<Integer> rangeSet = TreeRangeSet.create();
    rangeSet.add(Range.closed(3, 10));
    rangeSet.remove(Range.open(5, 7));
    SerializableTester.reserializeAndAssert(rangeSet);
  }
}