Howto create an Shim instance of Azure.Storage.Blobs.Models.BlobBlock

Question

I working on UnitTests and want to mock Azure.Storage.Blobs, what is working so long but for ShimBlockBlobClient.GetBlockListaSync (GetBlockListAsyncBlockListTypesStringBlobRequestConditionsCancellationToken) I running into a problem.

For the resulting List I need to create a Azure.Storage.Blobs.Models.Fakes.ShimBlockList containing two lists of Azure.Storage.Blobs.Models.BlobBlock. BlobBlock has no public constructor and the generated ShimBlobBlock has also no public construtor.

var fake = new Azure.Storage.Blobs.Specialized.Fakes.ShimBlockBlobClient()
{
    /*Some other Fake Func<> definitions*/
    ,
    GetBlockListAsyncBlockListTypesStringBlobRequestConditionsCancellationToken = 
       async (type, stringValue, condition, token) =>
       {
           await Task.Delay(1);
           return GetBlockList();
       }
};

ar baseClass = new Azure.Storage.Blobs.Specialized.Fakes.ShimBlobBaseClient(fake)
{
    NameGet = () => name,
    /* Some more Fake Func<> definitions*/
};

private static Response<BlockList> GetBlockList()
{
    var commited = new List<Azure.Storage.Blobs.Models.BlobBlock>();
    commited.Add(new BlobBlock("1", Data.Length)); // How to add here some value to the List
    /*commited.Add(new ShimBlobBlock()); does not work as it is generated as private construcor*/


    return new Azure.Fakes.StubResponse<Azure.Storage.Blobs.Models.BlockList>()
    {
         ValueGet = () =>
         {
              return new Azure.Storage.Blobs.Models.Fakes.ShimBlockList()
              {
                  CommittedBlocksGet = () => { return commited; },
                  UncommittedBlocksGet = () => { return new List<Azure.Storage.Blobs.Models.BlobBlock>(); },
                   };

               }
         };
}

As ShimBlobBlock.AllInstances not contain a replacement for Constructors I can not use that what was my secound try.