Creating a base HTTP service
In order for an app to communicate with an API via HTTP, it needs an HTTP library. Since we are using .NET and C# to build a Xamarin.Forms app, we can leverage a library called System.Net.Http.HttpClient. The .NET HttpClient provides a mechanism to send and receive data via standard HTTP methods, such as GET and POST.
Continuing to keep separation and abstraction key to our app architecture, we want to keep the specific logic related to the HttpClient separate from the rest of the app. In order to do this, we will write a base service class in our core library that will be responsible for handling HTTP communications in a generic way. This provides a building block for any domain-specific data services we might need to write; for example, a service that is responsible for working with log entries in the API. Any class that will inherit from this class will be able to send HTTP request messages using standard HTTP methods (such as GET, POST, PATCH, and...
