/// This macro is equivalent to `if !condition { return Err(From::from($err)) }`.

/// This macro is equivalent to `if !$cond { return Err(From::from($err)); }`.

/// Similar to `assert!`, `ensure!` takes a condition and exits the function
/// if the condition fails. Unlike `assert!`, `ensure!` returns an `Error`,
/// it does not panic.

/// Analogously to `assert!`, `ensure!` takes a condition and exits the function
/// if the condition fails. Unlike `assert!`, `ensure!` returns an `Error`
/// rather than panicking.

/// #

/// #     let resource = 0;