[Test][C++] Fix flaky ReaderTest.testAsyncRead #1063

Job	Run time
Formatting Check	1m 47s
Run unit tests	26m 26s
Lint	38m 41s
Build the Wireshark dissector (ubuntu-latest)	33s
Build CPP Client on ${{ matrix.name }}	0s
Build CPP Client on macOS with static dependencies	8m 25s
Build with the C++20 standard	5m 34s
Build ${{ matrix.pkg.name }} ${{ matrix.cpu.platform }}	0s
Check Completion	0s
Run unit tests	32m 24s
Lint	38m 41s
Build the Wireshark dissector (ubuntu-latest)	33s
Build with the C++20 standard	5m 34s
Build CPP Client on macOS with static dependencies	8m 25s
Formatting Check	1m 47s
Build CPP Client on Windows x86	56m 37s
Build CPP Client on Windows x64	1h 1m 0s
Build Alpine x86_64	28m 42s
Build RPM x86_64	20m 29s
Build Deb x86_64	20m 25s
Check Completion	3s
	5h 56m 6s

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