Make LeaseImpl.keepAliveOnce subject for retry policy (to retry on healthy etcd node if current node is broken)

[yakuninv]

Is your feature request related to a problem? Please describe.

We have a problem with this specific way of LeaseImpl.keepAliveOnce lease extention if etcd instance we attempt to connect is not available. Unlike other APIs like KVImpl or LockImpl which apply retry logic (in execute() call) and attempt to resend request if current node is not available or authenitcation is failed, this method just ends exceptionally, which is confusing and requires clients to write additional code for handling such use cases.

Describe the solution you'd like

Would it be possible to have variation of keepAliveOnce() that would apply retry policy same as other APIs do?
Can be separate method or new parameter in existing signature?