* Enable keys() to list elements without fetching values from server
* Add concurrency control and cancel to CI workflows
Signed-off-by: Tao He <sighingnow@gmail.com>
* Add more variants for etcd::Watcher's constructor.
* Use ASAN for testing on CI.
* Revert "Use ASAN for testing on CI."
This reverts commit 6ccc2161da.