Timer (metric interface 0.13.2 API)

所有方法实例方法抽象方法默认方法
限定符和类型	方法和说明
`Rate`	`getImmutableRate()` It's not safe to use the update interface of this rate
`HistogramSnapshot`	`takeSnapshot()` take snapshot of timer
`void`	`update(long duration, TimeUnit unit)` update time of timer
`default void`	`updateMicros(long durationMicros)` update timer by microseconds
`default void`	`updateMillis(long durationMillis)` update timer by millisecond
`default void`	`updateNanos(long durationNanos)` update timer by nanoseconds

void update(long duration,
            TimeUnit unit)

update time of timer

default void updateMillis(long durationMillis)

update timer by millisecond

default void updateMicros(long durationMicros)

update timer by microseconds

default void updateNanos(long durationNanos)

update timer by nanoseconds

getImmutableRate
```
Rate getImmutableRate()
```
It's not safe to use the update interface of this rate

接口 Timer