I would like to use my own Azure Blob storage for local development. 

I have considered the documentation here - https://docs.developers.optimizely.com/content-management-system/docs/how-to-add-azure-blob-provider-to-your-net-core-application 
i.e.

#

using EPiServer.ServiceLocation;
using Microsoft.Extensions.DependencyInjection;
using System;

namespace SampleBlob {
  public class Startup {
    public void ConfigureServices(IServiceCollection services) {
      services.AddAzureBlobProvider("Azure", o => {
        o.ConnectionString = {
          The Azure storage connection string
        };
        o.ContainerName = {
          The container name
        };
      });
    }
  }
}

... but this does not even compile :( 

I've tried the following in my startup class (note, that's not the real connection string). This compiles...

services.AddAzureBlobProvider(o =>
{
        o.ConnectionString =
                "DefaultEndpointsProtocol=https;AccountName=my_account_name;AccountKey=my_account_key;EndpointSuffix=core.windows.net";
        o.ContainerName = "my_container_name";
 });

... but when the app starts, I get an exception with message 'No valid combination of account information found."

I have checked in Azure Storage Explorer and the connection string works. So I must be missing a step in configuring this in Optimizely.

Any advice would be greatly appreciated