[FunctionName("MyTestFuncion")]
[StorageAccount("StorageConnectionAppSetting")]

public static async Task Run([EventHubTrigger("myeh", Connection = "EHConnection")] EventData[] events,
        Binder binder,
        ILogger log)
    ...

    using (var writer = await binder.BindAsync<TextWriter>(
                        new BlobAttribute("<container>/{rand-guid}.json")))
                    {
                        writer.Write(<what you want to write>);
                    }