### What it does
Checks for calculation of subsecond microseconds or milliseconds
from other `Duration` methods.

### Why is this bad?
It's more concise to call `Duration::subsec_micros()` or
`Duration::subsec_millis()` than to calculate them.

### Example
```
let micros = duration.subsec_nanos() / 1_000;
let millis = duration.subsec_nanos() / 1_000_000;
```

Use instead:
```
let micros = duration.subsec_micros();
let millis = duration.subsec_millis();
```