@Override
	public boolean identical(final Tree<?, ?> other) {
		return other == this ||
			other instanceof FlatTreeNode<?> node &&
			node._index == _index &&
			node._nodes == _nodes;
	}
Return a sequence of all <em>mapped</em> nodes of the whole underlying
tree. This is a convenient method for
{@snippet lang="java":
final ISeq<B> seq = stream()
    .map(mapper)
    .collect(ISeq.toISeq());
}

@param mapper the mapper function
@param <B> the mapped type
@return a sequence of all <em>mapped</em> nodes
jenetics.ext/src/main/java/io/jenetics/ext/util/FlatTreeNode.java