Create a daemon thread pool for etcd client & Add name format for ExecutorService (#167)

[ti-srebot]

cherry-pick #167 to release-3.1
You can switch your code base to this Pull Request by using git-extras:

# In client-java repo:
git pr https://github.com/tikv/client-java/pull/168

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/client-java.git pr/168:release-3.1-5265d3fd7b9c

---

What problem does this PR solve?

When my main thread is finished with all the tasks processed, this pool will prevent my program shutting down.
TiDBCatalogDemo.java

What is changed and how it works?

1. Create a daemon thread pool for etcd client
2. Add name format for ExecutorService

Check List

• Manual test (add detailed scripts or steps below)
  Test in local with version 3.0.1, thread stack :

"PDClient-tiflash-replica-pool-0@8667" daemon prio=5 tid=0x46 nid=NA waiting
  java.lang.Thread.State: WAITING
	  at sun.misc.Unsafe.park(Unsafe.java:-1)
	  at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	  at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
	  at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
	  at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
	  at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
	  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
	  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	  at java.lang.Thread.run(Thread.java:748)
"PDClient-update-leader-pool-0@8666" daemon prio=5 tid=0x45 nid=NA waiting
  java.lang.Thread.State: WAITING
	  at sun.misc.Unsafe.park(Unsafe.java:-1)
	  at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	  at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
	  at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
	  at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
	  at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
	  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
	  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	  at java.lang.Thread.run(Thread.java:748)
"etcd-conn-manager-pool-0@9096" daemon prio=5 tid=0x48 nid=NA waiting
  java.lang.Thread.State: WAITING
	  at sun.misc.Unsafe.park(Unsafe.java:-1)
	  at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
	  at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
	  at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
	  at java.util.concurrent.SynchronousQueue.poll(SynchronousQueue.java:941)
	  at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1073)
	  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
	  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	  at java.lang.Thread.run(Thread.java:748)

Related changes

• Need to cherry-pick to the release branch

[ti-srebot]

/run-all-tests

[birdstorm]

LGTM

[birdstorm]

/merge

[ti-srebot]

/run-all-tests