CountingLatch (Alluxio Parent 2.2.3-SNAPSHOT API)

```
public class CountingLatch
extends Object
```
Similar to CountDownLatch except that the count can either be increased or decreased. A thread can wait until the count reaches 0. Other threads can increase or decrease the count concurrently. When count reaches 0, if there is a thread waiting for state 0, the thread will be waken up, and other threads trying to increase the count are blocked. If there is no thread waiting for state 0, then other threads can keep increasing the count. Methods can be run concurrently from different threads, the paired methods(inc() and dec(), await() and release()) do not need to be called in the same thread. An example usage is to synchronize FileSystemContext reinitialization with the ongoing RPCs. See alluxio.client.fs.FileSystemContextReinitializer for more details.

Constructors
Constructor and Description
`CountingLatch()`

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`await()` Blocked during awaiting the counter to become zero.
`void`	`dec()` Decreases the counter.
`void`	`inc()` Increases the counter.
`void`	`release()` Unblocks threads blocked on calling `inc()`.

Class CountingLatch