@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		TailContents<?> other = TailContents.class.cast(obj);
		if (contents == null) {
			if (other.contents != null)
				return false;
		} else if (!contents.equals(other.contents))
			return false;
		if (size != other.size)
			return false;
		return true;
	}