Future features

[icweaver]

asdf members mentioned wanting to put a comparison table of supported features for different language implementations of the spec on their website. Just opening an issue here to track some of the gaps that we currently have / could aim to add in future releases:

• File streaming (will be especially useful for large Roman files)
• Exploded form
• Transforms (good for working with native Julia objects)
• WCS
• Documentation for creating your own converter. Would this lend itself well to package extensions? Prior art here for astro-specific applications
• Direct construction of an ASDF.ASDFFile object from a dict, instead of needing to round-trip through ASDF.write_file, ASDF.load_file
• Schema validation. Something like JSONSchema.jl may be useful for this

Additionally, here are some behind-the-scenes improvements that might be nice to have:

• Better tree printing. Maybe go with BFS instead of DFS, similarly to the python impl
• Automated roundtrip testing between Julia and Python impl. PythonCall.jl would be useful for this
• Automated benchmarks with AirspeedVelocity.jl