expose op.isOptsWithFromKey and op.isOptsWithPrefix

[CaojiamingAlan]

Fix #16217

Please read https://github.com/etcd-io/etcd/blob/main/CONTRIBUTING.md#contribution-flow.

[ahrtr]

They are already supported in #13334.

[CaojiamingAlan]

They are already supported in #13334.

The exported methods in #13334 takes a list of OpOption as parameter, which means the user needs to keep the options of the op if he or she wants to check the fields isOptsWithFromKey and isOptsWithPrefix later. what I am trying to do here is to expose those fields directly.

[ahrtr]

if he or she wants to check the fields isOptsWithFromKey and isOptsWithPrefix later

Yes, I understand that, but actually I don't see a real such use case. After the WithFromKey or WithPrefix is evaluated, users only care about the field end.

Of course, adding two methods (what this PR does) is harmless, but also unnecessary. I am neutral to this.

[jmhbnz]

This gets a tentative approval from me. At the code level I see no issue, and we have had #16217 opened by a user asking for this for the purpose of making detailed logs in an application.

It still seems like a nice to have more than anything so I defer to maintainers to make final decision. @changhoi please feel free to add any additional context here or in the issue in support of the pr.

[changhoi]

As described in PR, if the feature is added, our team will add more details to the log depending on whether Operation has a Prefix option.

Also, since there are other flag accessors, it seems natural to add them if there are no problems :)