/// Convenient wrapper to be able to use `try!` and such in the main. You can
/// use it with a separated function:
///
/// ```
/// # #[macro_use] extern crate error_chain;
/// # error_chain! {}
/// # fn main() {
/// quick_main!(run);
/// # }
///
/// fn run() -> Result<()> {
/// Err("error".into())
/// }
/// ```
///
/// or with a closure:
///
/// ```
/// # #[macro_use] extern crate error_chain;
/// # error_chain! {}
/// # fn main() {
/// quick_main!(|| -> Result<()> {
/// Err("error".into())
/// });
/// # }
/// ```
///
/// You can also set the exit value of the process by returning a type that implements [`ExitCode`](trait.ExitCode.html):
///
/// ```
/// # #[macro_use] extern crate error_chain;
/// # error_chain! {}
/// # fn main() {
/// quick_main!(run);
/// # }
///
/// fn run() -> Result<i32> {
/// Err("error".into())
/// }
/// ```
/// Represents a value that can be used as the exit status of the process.
/// See [`quick_main!`](macro.quick_main.html).