Add more comprehensive debugging instrumentation

[suyashkumar]

There are all sorts of odd or even non-conformant DICOMs out in the world.

When we encounter parser failures on a DICOM (for both the current and the in progress rewrite), it would be good to be able to toggle a debug mode flag that can help us better dig into parsing failures and provide helpful information. Ideally if this information is not PHI (e.g. just DICOM tags, other general info), it would also be an easy way for users to report bugs and paste their output without having to explicitly share the DICOMs (though that would of course be the best if possible).

Going to spitball some helpful general debug information:

• Current tag being read
• What tags have been read so far
• Manufacturer info (if read)
• Number of bytes read total
• Status of the dicom decoder's limits (if any) and current position

It's possible to implement this sort of info with a debug log level at first. We may even want to specify two debug levels--one that will only output general non-PHI info, and maybe another that will output more detailed info like the metadata read so far, etc.

Need to think about this a little more too

[tbshill]

Hey Suyashkumar,

Thanks for making this library open source. I have benefited from your work and I would love to help contribute to this project. Is this issue specific to the dicomutil executable or are you looking to introduce flags into the decoder api.

Thanks, -Braden Shill