fix #14685 tests/async/t7758.nim flaky (#14721)
fix #14685 tests/async/t7758.nim flaky (#14721)

* fix #14685 tests/async/t7758.nim flaky

* address comment

* address comment
dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim