Q:

Trouble with Azure Function v3 in C#

I have a set of Azure Functions, written in C#, and running on Azure Function v2 runtime (.NET Core 2.2), which work just fine.
Now I was going to create a new set of Azure Function and I want to use the v3 runtime (.NET Core 3.1). However, when "transferring" the code from my existing code base, I ran into this problem: I have a Startup.cs file that's setting up the Dependency Injection for the Azure Functions, and this is what it looked like in my Azure Function v2 project:
[assembly: FunctionsStartup(typeof(MyCorp.MyProject.Infrastructure.Startup))]
namespace MyCorp.MyProject.RisWebportalService.Infrastructure
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddHttpClient();
            // more lines here, setting up DI
        }
    }
}

When I tried to use this in the Azure Function v3 project, I get an error on the builder.Services.AddHttpClient(); line - seems IFunctionsHostBuilder in v3 doesn't have this extension method anymore......
So what do I do instead? I cannot seem to find any really useful documentation on any breaking changes in Azure Function runtime between v2 and v3  - any pointers? 

A:

You should install the package Microsoft.Extensions.Http, version 3.1.3.
The test result after installing it:

I found the same issue here.

