in fc/entry.go [114:124]
func StartHandlerWithContext(ctx context.Context, handler interface{}, funcType functionType) {
startFunction := runtimeAPIStartFunction
config := os.Getenv(startFunction.env)
if config != "" {
// in normal operation, the start function never returns
// if it does, exit!, this triggers a restart of the lambda function
err := startFunction.f(ctx, config, handlerWrapper{handler, funcType}, lifeCycleHandlers)
logFatalf("%v", err)
}
logFatalf("expected ali FC environment variables [%s] are not defined", startFunction.env)
}