Retrofitting isolation in a simple application

This first part of the tutorial is going to focus on modify our application to add sandboxing, the next part will focus on recompiling our library with wasm to enforce isolation.

In this example, we're going to use the noop sandbox backend. The noop sandbox does not actually enforce isolation, it is simply a tool that makes it easier to port new libraries to RLBox. The noop sandbox does nothing more than turn our calls into the RLBox sandbox into normal function calls to the library we already have linked in our application.

The reason for this noop backend is that it supports incrementally porting our application. Instead of having to worry about trying to change all our library interfaces at once (to account for ABI differences between a sandbox and our normal library), and deal with the resulting head-aches. We can change gradually change our function calls from normal library calls, to sandbox calls, and at each step test that our application continues to work as expected.