Macro test_cbor_roundtrip

macro_rules! test_cbor_roundtrip {
    ($type:ty) => { ... };
    ($type:ty, $iterations:expr) => { ... };
    ($type:ty, $iterations:expr, $print:expr) => { ... };
    ($type:ty, $iterations:expr, $print:expr, $name:ident) => { ... };
}