Tszip can't decompress with struct metadata

[hyanwong]

In the attached file, there is struct metadata associated with the tree sequence at the top level (a simple array). Tszip can load the .trees file, and compress it to .tsz, but then can't load the .tsz file it just made:

import tszip

ts = tszip.load("test.trees")
tszip.compress(ts, "tmp.tsz")
tszip.load("tmp.tsz")  # fails with ValueError: bytes must be in range(0, 256)

test.trees.zip

Here's the debug output

File ...tszip/compression.py:329, in decompress_zarr(root)
    327     dict_repr[key] = bytes(value).decode("utf-8")
    328 elif key.endswith("metadata"):
--> 329     dict_repr[key] = bytes(value)
    330 else:
    331     dict_repr[key] = value

ValueError: bytes must be in range(0, 256)