The `initialNow` prop is used to avoid content mismatches when Universal/SSR apps render date values using components like `<FormattedRelative>`.
If this value is created in `render()`, then the server will generate it and then the client will also generate it during hydration / initial render, resulting in two different values and content mismatches like:
> Warning: Text content did not match. Server: "in 1,741,545 seconds" Client: "in 1,741,543 seconds"
If the value is instead generated in `getInitialProps`, then the client's initial rendering will match because it will use the same value sent down by the server.