@Nullable
    default <T> ClientBuilderParams clientBuilderParams(T client) {
        return unwrap(client, ClientBuilderParams.class);
    }
Returns the {@link ClientBuilderParams} held in {@code client}. This is used when creating a new derived
{@link Client} which inherits {@link ClientBuilderParams} from {@code client}. If this
{@link ClientFactory} does not know how to handle the {@link ClientBuilderParams} for the provided
{@code client}, it should return {@code null}.
core/src/main/java/com/linecorp/armeria/client/ClientFactory.java