I know, that Retrofit uses OkHttp internally.
But, I can see that some developers provided applying of approach as bellow

```
return new Retrofit.Builder()
        .baseUrl(BuildConfig.API_ENDPOINT)
        .client(getClient()) // we can add OkHttpClient client there

```

So, can someone clarify why this needed?

I have heard that this can be helpful for testing, when we can apply custom Interceptor during mocking of HTTP requests