Function get_option_value 

pub fn get_option_value<Opt>(
    name: &str,
    opts: &OptionOpts,
) -> Result<Opt, Error>
where
    Opt: FromObject,

Binding to nvim_get_option_value().

Gets the local value of an option if it exists, or the global value otherwise. Local values always correspond to the current buffer or window, unless buf or win is set in opts.