public ArmeriaRetrofitBuilder addCallAdapterFactory(CallAdapter.Factory factory) {
        retrofitBuilder.addCallAdapterFactory(requireNonNull(factory, "factory"));
        return this;
    }
Adds the specified call adapter factory for supporting service method return types other than {@link
Call}.
@see Retrofit.Builder#addCallAdapterFactory(CallAdapter.Factory)
retrofit2/src/main/java/com/linecorp/armeria/client/retrofit2/ArmeriaRetrofitBuilder.java