anchor.diff:              let handle =
                   match checkSum doc.File with
                   | Some (hashAlg, checkSum) ->
  -                    let h = 
  +                    let dbgInfo = 
                           (serializeDocumentName doc.File,
                            metadata.GetOrAddGuid(hashAlg),
                            metadata.GetOrAddBlob(checkSum.ToImmutableArray()),
  
positive.code:                     match includeSource doc.File with
                      | None -> ()
                      | Some blob ->
                          metadata.AddCustomDebugInformation(DocumentHandle.op_Implicit(h),
                                                             metadata.GetOrAddGuid(embeddedSource),
                                                             metadata.GetOrAddBlob(blob)) |> ignore
                      h
                  | None ->
                      let h = 
                          (serializeDocumentName doc.File,
                           metadata.GetOrAddGuid(System.Guid.Empty),
                           metadata.GetOrAddBlob(ImmutableArray<byte>.Empty),
                           metadata.GetOrAddGuid(corSymLanguageTypeFSharp)) |> metadata.AddDocument
                      h
              index.Add(doc.File, handle)
          index
  
  
negative.code:     static let chunkSize = 32 * 1024
      let builder = new BlobBuilder(chunkSize)
  
      override this.CanWrite = true
      override this.CanRead  = false
      override this.CanSeek  = false
      override this.Length   = int64(builder.Count)
  
      override this.Write(buffer:byte array, offset:int, count:int) = builder.WriteBytes(buffer, offset, count)
      override this.WriteByte(value:byte) = builder.WriteByte(value)
  