Struct Bootstrap 

#[non_exhaustive]
pub struct Bootstrap {
    pub config: Store,
    pub logging: Handle,
}

What init hands back: the configuration everything else reads, and the handle that keeps the logging workers alive.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

config: Store

The merged configuration store.

logging: Handle

Keep this for the process lifetime; it is what flush and shutdown are driven through.