use fuel_types::ContractId;
pub struct ReturnData {
    id: ContractId,
    data: Vec<u8>,

You can handle functions that produce a ReturnData receipt type by using the returned type as a function parameter.

Note: the example below will run both when the type MyStruct is logged as well as when MyStruct is returned from a function.

fn handle_return_data(data: MyStruct) {
  // handle the returned data