Can't convert TIFF with multiple annotations

Hi Bas,

I encountered an issue while trying to convert a TIFF file with multiple annotations to PDF. Here is the error message:

```
C:\Users\...\Desktop\tiffconvert_release>tiffconvert -pcpng input-file.tiff pdf output-file.pdf
_TIFFVSetField: buffer: Null count for "Tag 32934" (type 4, writecount -3, passcount 1).
```

What could this be related to? Could this issue be related to the annotations in the input file not meeting the required format?
I'm using your latest release package. I've also attached the input file for your review.

[input-file.zip](https://github.com/Imagine-Programming/tiffconvert/files/15235666/input-file.zip)

Thanks in advance!

Reproduce the failure with the attached input-file.zip using the documented tiffconvert command and the latest release package. Start by tracing handling of TIFF files with multiple eiStream/Wang annotations and Tag 32934; done means the attached file converts to PDF without the reported error, or the required annotation format is clearly documented.

Written by the indexing model from the issue text.