mzIdentML Usage Patterns

[mobiusklein]

The API for MzIdentMLWriter is much rougher than MzMLWriter, and was designed with the assumption the user would provide generators to lazily provide all of the large collections. This makes it less intuitive to build in complex logic to prepare members of those collections on the fly.

I'm opening this issue to initiate discussion of what would be ideal. @JB-MS, if you have a chance to take a look and let me know how you plan to use the API, we might come to a better design.