2.3: Avoid warnings on ComputesNanosecondTimestamps (#21)
* Avoid warnings on ComputesNanosecondTimestamps * Tweaks - Compute `strlen` once. - `microtime(true)` can return different number of decimals: These are all valid: ``` 1706498205.1234 1706498205.123 1706498205.12 1706498205.1 ``` * Refactor and tests * Improve float length and more tests