It seems odd to use a helper function for https and Uri for http. Why not include the protocol in the format string like so:

```C#
string blobEndpointFormat = "{0}://{1}.blob.core.windows.net/";
string endpoint = string.Format(blobEndpointFormat, useHttps ? "http" : "https", accountName);
return new Uri(endpoint):
```

or something along those lines?