Macro create_batch_result_struct 

macro_rules! create_batch_result_struct {
    ($struct_name:ident, $success_type:ident, $map_key_type:ident) => { ... };
}

Creates a batch result struct named after the first parameter. Uses the second parameter as the success type. Uses the third parameter as the key type for the HashMaps. The type will be a uniffi Record and it will have a From impl for BatchResult.