protected static io.grpc.netty.shaded.io.netty.handler.ssl.ClientAuth of(final ClientAuth clientAuth) {
        switch (clientAuth) {
            case NONE:
                return io.grpc.netty.shaded.io.netty.handler.ssl.ClientAuth.NONE;
            case OPTIONAL:
                return io.grpc.netty.shaded.io.netty.handler.ssl.ClientAuth.OPTIONAL;
            case REQUIRE:
                return io.grpc.netty.shaded.io.netty.handler.ssl.ClientAuth.REQUIRE;
            default:
                throw new IllegalArgumentException("Unsupported ClientAuth: " + clientAuth);
        }
    }
Converts the given client auth option to netty's client auth.

@param clientAuth The client auth option to convert.
@return The converted client auth option.
grpc-server-spring-boot-starter/src/main/java/net/devh/boot/grpc/server/serverfactory/ShadedNettyGrpcServerFactory.java