setupBridge method
Implementation
@override
bool setupBridge(String channelName, void Function(dynamic args) fn) {
final channelFunctionCallbacks =
JavascriptRuntime.channelFunctionsRegistered[getEngineInstanceId()]!;
if (channelFunctionCallbacks.keys.contains(channelName)) return false;
channelFunctionCallbacks[channelName] = fn;
return true;
}