LogFlusher (starrocks-bdb-je 18.3.17 API)

```
public class LogFlusher
extends Object
```
Flush the log buffers (and write queue) periodically to disk and to the file system, as specified by EnvironmentConfig.LOG_FLUSH_SYNC_INTERVAL and EnvironmentConfig.LOG_FLUSH_NO_SYNC_INTERVAL. Currently flushing occurs if any transactions were committed during the interval. In the future we may want to flush if there were no writes or fynscs in the interval, to allow specifying an even smaller interval for NO_SYNC flushing. This would mean that the wakeup interval should be the config interval divided by 2.

Constructors
Constructor and Description
`LogFlusher(EnvironmentImpl envImpl)`

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`configFlushTask(DbConfigManager configMgr)` Applies the new configuration, then cancels and reschedules the flush tasks as needed.
`void`	`requestShutdown()`
`void`	`shutdown()`

Class LogFlusher