RUNTIME: Variable forcing now uses limited list and buffer instead of systematical instance tree traversal and in-tree "fvalue" to keep track of forced value for pointed variables (external, located). Pointer swapping is performed when forcing externals and located, with backup being restored when forcing is reset. Retain still uses tree traversal.

# opcua/__init__.py

from __future__ import absolute_import

from .client import OPCUAClient

# class RootClass(object):
#     XSD = """<?xml version="1.0" encoding="ISO-8859-1" ?>
#     <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
#     </xsd:schema>
#     """
#     CTNChildrenTypes = [("OPCUAClient", OPCUAClient, "OPCUA Client")]
#