How to check if the viewer is initialized complete?

```
Hi all,

I would like to ask if there are any ways to check if the viewer is initialized
complete after the first viewer.init() and update() call.

Since it seems to be async functions, so if I want to change object/texture
before it is loaded complete errors occur. Are there any callbacks or checking
to check if the canvas is inited as is ready?

```

Original issue reported on code.google.com by `passerby...@gmail.com` on 17 Dec 2013 at 8:37

Start by tracing the viewer.init() and update() calls and the canvas loading lifecycle. Determine whether the viewer exposes a completion callback or readiness check before object or texture changes are made; done means documenting or providing a reliable way to avoid errors while initialization is still in progress.

Written by the indexing model from the issue text.