return the clientid (as returned by the owner command) of the client/server which updated the public variable as third parameter to the _this variable available inside the context of a PublicVariableEventHandler.
e.g.
"somevariable" addPublicVariableEventHandler {
switch (_this select 2) do {
case (clientIDx): {
//variable updated by client x
};
case (clientIDy): {
//variable updated by client y
};
};};