Use Awaitility to instead of Thread sheep method.

[mattisonchao]

• Use Awaitility to avoid busy waiting.
• Refactor some code to Java8

[eolivelli]

LGTM

we are using a lot Awaiatility in Apache Pulsar.

would you like to follow up and enhance more tests ?

[eolivelli]

@tisonkun @Randgalt @cammckenzie
if you have time please take a look, the change is simple

I like Awaitility, we started to use it in Pulsar in order to make tests code cleaner and in general reduce flakyness

[mattisonchao]

LGTM

we are using a lot Awaiatility in Apache Pulsar.

would you like to follow up and enhance more tests ?

Sure, I will do that.

[tisonkun]

LGTM. Thanks for your work!

I'd suggest separate a commit to refactor lambda expression for your next contributions @mattisonchao

[eolivelli]

here you are adding an implicit timeout of 10 seconds
I am fine with it, as far as it does not make the test become flaky

[eolivelli]

@mattisonchao I have merged this PR.

but in Curator we use JIRA to track the work

can you please create a ticket here and link it to this PR ?
https://issues.apache.org/jira/secure/Dashboard.jspa

Usually we require that the commit message reports the JIRA ticket ID.

@tisonkun I was too quick in using the Git Hub merge button :(
we know have a script in Curator that prevents us from doing this kind of errors while committing PRs