* Add callTick and stream cancellation tests.
* Fix stepsAsync() test.
* Cancellation changes.
* Update and add more cancellation tests.
* Fix Posix shutdown call to handle ENOTCONN error.
* With new changes to to cancellation its now possible.
* Refactor testsoon.nim to not produce artifacts after tests are finished.
* Debugging MacOS issue.
* Adjust flaky test times.
* Fix issue.
* Add test for issue #334 which was also addressed in this PR.
Avoid `break` in problematic test.
* Add noCancelWait() call which prohibits cancellation.
Fix closeWait() calls to use noCancelWait() predicate.
Adding sleep to flaky MacOS test.
* Remove all debugging echoes.
* Fix cancelAndWait() which now could perform multiple attempts to cancel target Future (mustCancel behavior).
* Fix issues revealed by switch to different cancelAndWait().
* Address review comments.
* Fix testutils compilation warning.
* Rename callTick() to internalCallTick().
* Add some documentation comments.
* Disable flaky ratelimit test.
* Rename noCancelWait() to noCancel().
Address review comments.
Eugene Kabanov
Tanguy
Jacek Sieka