How to mock grpc model in Swift

Issue #306

let json: [String: Any] = [
    "id": "123",
    "name": "Thor",
    "isInMarvel": true
]

let data = try JSONSerialization.data(withJSONObject: json, options: [])
let string = String(data: data, encoding: .utf8)!
return try Hero(jsonString: string)

If we use withValue from How to simplify struct mutating in Swift then we can mock easily

extension Hero {
    static func mock() -> Hero {
        return withValue(Hero()) {
            $0.id = "123"
            $0.name = "Thor"
            $0.isInMarvel = true
        }
    }
}