Blosc compression and compatibility with existing files

[braingram]

There are 2 known examples of blosc compression support for asdf files:

• https://github.com/abacusorg/abacusutils/blob/main/abacusnbody/data/asdf.py
• https://github.com/eschnett/asdf-cxx/blob/579539046f6ef44cde7093ca95bdaab60d9dd4b6/ndarray.cpp#L215C23-L215C28

Investigate if these are compatible and if they are compatible with asdf-compression.

asdf-cxx blosc

So far, a simple test attempting to read the example file produced for the asdf-cxx example:
https://github.com/eschnett/asdf-cxx/blob/main/demo-compression.cpp
in asdf (with asdf-compression installed) succeeds and all arrays equal the non-compressed array.
I was not able to test blosc2 as I don't have it installed (and I didn't immediately see it available through homebrew).

abacusutils blosc

Testing with the abacus test file:
https://github.com/abacusorg/abacusutils/blob/main/tests/Mini_N64_L32/halos/z0.000/field_rv_A/field_rv_A_000.asdf
and the asdf-compression code at 2cc262d
I get the following error:

error: Error 19295 : not a Blosc buffer or header info is corrupted

This is possibly due to how the abacus compressor splits up the contents into blocks:
https://github.com/abacusorg/abacusutils/blob/b76af8f302f45b7064d7929f3c1bcd9960329788/abacusnbody/data/asdf.py#L82-L88