Prossible perf_hooks memory leak detected

It seems nanobus creates a performance entry on event emit and never clear the entry, so after a long time of using, more and more entries of performance will be in memory.

key code here:
```js
var emitTiming = nanotiming(this._name + "('" + eventName + "')")
var listeners = this._listeners[eventName]
if (listeners && listeners.length > 0) {
this._emit(this._listeners[eventName], data)
}

if (this._starListeners.length > 0) {
this._emit(this._starListeners, eventName, data, emitTiming.uuid)
}
emitTiming()
```
and warning message is:
```
(node:84217) Warning: Possible perf_hooks memory leak detected. There are 996 entries in the Performance Timeline. Use the clear methods to remove entries that are no longer needed or set performance.maxEntries equal to a higher value (currently the maxEntries is 150).
```

and my test code is here:
```js
const nanobus = require('nanobus')
const bus = nanobus()

bus.on('foo', () => {})

for (let i=0; i<1000; i++) {
bus.emit('foo', 'bus')
}
```

I see this message when I use webpack-serve which use nanobus as bus to emit events.

So I guess it's a bug?

Reproduce the warning with the provided nanobus loop and inspect the emit path containing the shown nanotiming code. Trace how performance entries are created and verify the completed change no longer leaves entries accumulating during repeated emits or triggers the perf_hooks warning.

Written by the indexing model from the issue text.