addConnectionStates = (a, b) => {
	if (a === true || b === true) return true;
	if (a === false) return b;
	if (b === false) return a;
	if (a === TRANSITIVE_ONLY) return b;
	if (b === TRANSITIVE_ONLY) return a;
	return a;
}
@param {ConnectionState} a first
@param {ConnectionState} b second
@returns {ConnectionState} merged