Malformed file by Arrow.write on a IOStream created with open(filename, "w")

[heliosdrm]

Context:
https://discourse.julialang.org/t/cannot-read-file-written-by-arrow-jl-in-python/97889/2

As mentioned in one of the answers, the file that results from:

open(filename, "w") do io
    Arrow.write(io, table)
end

does not include the magic "ARROW1" in the start/end, and there may be other problems.

It does work with Arrow.write(filename, table), though (filename being the path to the file).

[heliosdrm]

Closing: I just found that it is solved by using the keyword arg file=true, as documented. Sorry for the confusion.