On the server `props.initialMobxState` received by the `constructor` is a fully functioning mobx store that was instantiated by `getInitialProps()` only a few ticks earlier.
Thus, creating a new instance is unneccessary.
In the browser, however, `props.initialMobxState` is a hydrated plain object and thus the store needs to be initialized.
I spent far too much time fiddling with this example project before realizing it contained a bug in the store initialization logic and it was a bit more complex than it needed to be.
* The custom server was not needed
* The store-initialization did effectively the same thing twice for no reason
* And wrapping MyApp component in a HOC was wholly unnecessary indirection
My changes are split into four discrete commits for clarity.