Macro phony::hash_map

macro_rules! hash_map {
    () => { ... };
    ($key: expr => $value: expr) => { ... };
    ($key: expr => $value: expr; $init_capacity: expr) => { ... };
    ($($key: expr => $value: expr),*) => { ... };
    ($($key: expr => $value: expr,)*) => { ... };
}