fix: JET failure on Julia 1.13 (Array(::CDFVariable) inferred as Union{Nothing,...})

[Beforerr]

Julia 1 on CI now resolves to 1.13.1, where JET reports 4 errors in all/any on CDFVariable (src/variable.jl:81-82): Array(var::CDFVariable) infers as Union{Nothing, AbstractArray} because DiskArrays.readblock! on an abstract CDFVariable may resolve to DiskArrays methods returning nothing. Seen in run 36763211390; reproduced locally on origin/main with Julia 1.13.1.

Fix: Array and _record return their locally allocated dest instead of readblock!'s return value. Full test suite passes on 1.13.1.

[codecov]

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[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	0f858bf...	main / 0f858bf...
elx/full_load	0.0342 ± 0.0053 ms	0.0317 ± 0.0018 ms	1.08 ± 0.18
elx/sum_array	2.84 ± 0.75 μs	6.88 ± 1.7 μs	0.413 ± 0.15
elx/sum_lazy	5.22 ± 3.9 μs	6.76 ± 1.4 μs	0.772 ± 0.6
elx/sum_var_access	7.03 ± 1.3 μs	5.16 ± 4.5 μs	1.36 ± 1.2
elx/var_access	0.19 ± 0.001 μs	0.211 ± 0.01 μs	0.9 ± 0.043
mms/full_load	26.2 ± 12 μs	18.8 ± 1.9 μs	1.39 ± 0.65
mms/sum_array	0.0763 ± 0.0027 s	0.0769 ± 0.0046 s	0.991 ± 0.069
mms/sum_slice	2.96 ± 0.22 ms	2.87 ± 0.28 ms	1.03 ± 0.13
mms/sum_var_access	2.98 ± 0.22 ms	2.85 ± 0.26 ms	1.05 ± 0.12
mms/var_access	0.07 ± 0.01 μs	0.07 ± 0 μs	1 ± 0.14
time_to_load	0.268 ± 0.015 s	0.296 ± 0.013 s	0.905 ± 0.065

Memory benchmarks

	main	0f858bf...	main / 0f858bf...
elx/full_load	0.217 k allocs: 24.8 kB	0.217 k allocs: 24.8 kB	1
elx/sum_array	12 allocs: 28 kB	12 allocs: 28 kB	1
elx/sum_lazy	12 allocs: 28 kB	12 allocs: 28 kB	1
elx/sum_var_access	14 allocs: 28.3 kB	14 allocs: 28.3 kB	1
elx/var_access	1 allocs: 0.234 kB	1 allocs: 0.234 kB	1
mms/full_load	0.065 k allocs: 6.45 kB	0.065 k allocs: 6.45 kB	1
mms/sum_array	1.04 k allocs: 31.7 MB	1.04 k allocs: 31.7 MB	1
mms/sum_slice	0.069 k allocs: 1.29 MB	0.069 k allocs: 1.29 MB	1
mms/sum_var_access	0.069 k allocs: 1.29 MB	0.069 k allocs: 1.29 MB	1
mms/var_access	1 allocs: 0.219 kB	1 allocs: 0.219 kB	1
time_to_load	0.2 k allocs: 11.8 kB	0.2 k allocs: 11.8 kB	1