LatchSupport (starrocks-bdb-je 18.3.17 API)

```
public class LatchSupport
extends Object
```
Supports latch debugging. In JE test mode (when the JE_TEST system property is set), TRACK_LATCHES will be true and related debugging methods may be used to check the number of Btree latches held. CAPTURE_OWNER is also set to true if the system property JE_CAPTURE_LATCH_OWNER is defined to true. This will capture a stack trace when a latch is acquired exclusively, and the stack trace will be included in all error messages. Capturing the stack trace is expensive so this is off by default for unit testing.

Constructors
Constructor and Description
`LatchSupport()`

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static String`	`btreeLatchesHeldToString()`
`static void`	`clear()` Should be called when closing the environment, so that residual latches don't impact another environment that is opened
`static void`	`dumpBtreeLatchesHeld()`
`static void`	`expectBtreeLatchesHeld(int expectNLatches)`
`static void`	`expectBtreeLatchesHeld(int expectNLatches, String msg)`
`static int`	`nBtreeLatchesHeld()`

public static final boolean TRACK_LATCHES

public static final LatchTable btreeLatchTable

public static final LatchTable otherLatchTable

public static final LatchContext DUMMY_LATCH_CONTEXT

public static void expectBtreeLatchesHeld(int expectNLatches)

public static void expectBtreeLatchesHeld(int expectNLatches,
                                          String msg)

public static void dumpBtreeLatchesHeld()

public static String btreeLatchesHeldToString()

clear
```
public static void clear()
```
Should be called when closing the environment, so that residual latches don't impact another environment that is opened

Class LatchSupport