Triggered when init functions are about to be invoked.
startInitFunctionOrder will be triggered after this with additional info, in turn triggering multiple initFunctionInvoking and in turn initFunctionInvoked triggers. After the init functions were invoked, startInitFunctionOrder will be triggered again with additional functions, or endInitFunction will be triggered, finalizing the process.
This is the data
provided to the message event:
interface EventData {
eventName: 'startInitFunction',
type: string,
}