[c++] Modify ManagedQuery to perform async queries

[nguyenv]

Issue and/or context:

Across both APIs we have observed the SOMAArray intermittenly segfault when accessing the array. This occurs due to a race condition where we have multiple read queries and one query closes the array before the other queries have completed. When a query that has not completed tries to access a closed array, it segfaults. The solution is to modify the C++ ManagedQuery so that it performs async queries and waits for all query threads to complete before closing the SOMAArray.

Changes:

• Changes pulled from [python] NDArray read path #1817

[eddelbuettel]

LGTM but I am not very deep into std::future<> so merely commenting for now.

I am also a little fuzzy about when we actually launch multiple queries at once -- I had the (wrong, clearly) mental model that we launch one, and iterate if its status is incomplete.

[johnkerl]

This needs to be branched off main and then we can backport to release-1.6

At present it's branched off @mojaveazure 's feature-dev work which is unrelated to, and should not block, the 1.6.0 release we're trying to get out today

[johnkerl]

Meanwhile @nguyenv I really appreciate the debug, and am verifying it on #1943 -- which I will rebase later once this is merged to release-1.6 -- so #1943 will go back to being only apis/r/DESCRIPTION and apis/r/NEWS.md

[eddelbuettel]

Good catch @johnkerl -- I only saw 'one commit' and nodded and was asleep as to the branch it came from.

[codecov-commenter]

Codecov Report

Merging #1953 (0912b26) into main (dbd1089) will decrease coverage by 14.54%.
The diff coverage is n/a.

❗ Current head 0912b26 differs from pull request most recent head 3ab343c. Consider uploading reports for the commit 3ab343c to get more accurate results

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Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1953       +/-   ##
===========================================
- Coverage   62.81%   48.28%   -14.54%     
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  Files         106       72       -34     
  Lines       10037     6464     -3573     
===========================================
- Hits         6305     3121     -3184     
+ Misses       3732     3343      -389     

Flag	Coverage Δ
python	?
r	48.28% <ø> (ø)

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Components	Coverage Δ
python_api	∅ <ø> (∅)
libtiledbsoma	∅ <ø> (∅)

[gspowley]

LGTM! One minor suggestion.