Logging multiple times over the course of a programs lifetime

With v2.0.3, invoking the exported log [disables the hook](https://github.com/mafintosh/why-is-node-running/blob/v2.0.3/index.js#L26). I needed a more complete picture of what was going on during closing of an application because the answer to "why is node running" kept changing. Hence, I tried to sample open handlers as shown below.

```javascript
for (let i = 0; i < 10; i++) {
setTimeout(log, (i + 1) * 500);
}
```

However, this was obviously not possible. It worked with the following patch, in case anyone also needs this, and I am lightly suggesting it as an addition.

```patch
--- index.js
+++ index.js
@@ -23,9 +23,8 @@
function whyIsNodeRunning (logger) {
if (!logger) logger = console

- hook.disable()
logger.error('There are %d handle(s) keeping the process running', active.size)
- for (const o of active.values()) printStacks(o)
+ for (const o of [...active.values()]) printStacks(o)

function printStacks (o) {
var stacks = o.stacks.slice(1).filter(function (s) {
```

Start by reading index.js around whyIsNodeRunning and the hook handling described in the issue. Check how repeated calls to the exported log behave, then verify that sampling multiple times reports the current handles without stopping further tracking. The issue's patch shows the intended one-file scope and the relevant output path.

Written by the indexing model from the issue text.