Macro gear_common::wrap_counted_storage_map

macro_rules! wrap_counted_storage_map {
    (storage: $storage: ident, name: $name: ident, key: $key: ty, value: $val: ty, length: $len: ty) => { ... };
}

Same as wrap_storage_map!, but with length type parameter to auto-impl Counted trait of gear_common storage primitives.

Better to use Rust’s numeric types as Length.