This benchmark measures performance of various alternatives to interface cast, which is expensive.
The reason is that interface cast involves "duct type check", and cast to type just checks a type hash value inside iface.
Cases:
BenchmarkAssertStruct- Castanyto a concrete struct type (fastest).BenchmarkAssertIface- Cast to an interface.BenchmarkAssertWrapper- Cast to a concrete type and call a field that is an interface.