public void TestRemoveEdgeCase()
{
EqualityComparer <int> equalityComparer = EqualityComparer <int> .Default;
Func <int, int> getHashCode = value => Math.Abs(value) < 5 ? 0 : 1;
ImmutableTreeSet <int> .Builder set = ImmutableTreeSet.CreateBuilder(new SubsetHashCodeEqualityComparer <int>(equalityComparer, getHashCode));
set.UnionWith(Enumerable.Range(0, 10));
Assert.True(set.Remove(4));
Assert.False(set.Remove(4));
}
