Macro builder_with 

macro_rules! builder_with {
    ($field:ident, $type:ty) => { ... };
    ($field:ident, $type:ty, $doc:expr) => { ... };
}

Implement a builder pattern with_* prefix setter method.

Example

impl Config {
    mabi_core::builder_with!(name, String);  // Creates with_name()
}