Macro relay_protocol::derive_string_meta_structure

macro_rules! derive_string_meta_structure {
    ($type:ident, $expectation:expr) => { ... };
}

Derives the FromValue, IntoValue, and Empty traits using the string representation.

Requires that this type implements FromStr and Display. Implements the following traits:

• FromValue: Deserializes a string, then uses FromStr to convert into the type.
• IntoValue: Serializes into a string using the Display trait.
• Empty: This type is never empty.