Clarification on how to use "watch" in v0.13

Nice work. The refactoring in the latest version makes a lot of sense. I'm speaking based on my experience with the new use of the "builder" pattern.

I'm trying to workout how to "get from a to b" in such a way that I can use the ability to watch a configuration file. The type that I ended-up with does not support read nor write.

At some level, I recognize this is a bit of a naive question. Notwithstanding, here is what I have:

impl Settings {
    pub fn new() -> Result<Self, ConfigError> {
        let mode = env::var("RUST_ENV").unwrap_or_else(|_| "Development".into());

        let settings = Config::builder()
            .add_source(File::with_name(CONFIG_FILE_PATH))
            // use env Development, Production or Testing to set override
            .add_source(File::with_name(&format!("{}/{}", CONFIG_FILE_ROOT, mode)).required(false))
            .add_source(Environment::default().separator("_"))
            .build()?;

        settings.try_deserialize()
    }
}

lazy_static! {
    pub static ref CONFIG: Settings = Settings::new().unwrap();
}

Clearly I need to "hold-off" on instantiating the Settings so that I can use the read and write functions per the example.

async fn reload_config() -> impl IntoResponse {
    config::CONFIG.write().unwrap().refresh().unwrap();
    show_settings()
}
fn show_settings() -> String {
    format!(
        " * Settings :: \n\x1b[31m{:?}\x1b[0m",
        config::CONFIG
            .read()
            .unwrap()
            .clone()
            .try_deserialize::<HashMap<String, String>>()
            .unwrap()
    )
}

Without calling try_deserialize, and later the calling Settings::new().unwrap() to set the value of static ref, I don't get the expected type "Settings".

What is the type that I should be using to host the settings so that I can create the "Settings" instance upon the read and write combination?

Start with the v0.13 builder and watch example, then trace the Config::builder, build, try_deserialize, read, write, and refresh calls shown in the issue. Determine the supported lifecycle and type for watched configuration, and document a minimal example covering initialization, refresh, and reading Settings.