Preconditions are meant to be an alternative way to ensure that a precondition for a specific method is given.

• checkArgument()
• checkArgNotNull()
• checkNotNull()
• checkElementIndex()
• checkPositionIndex()
• checkPositionIndexes()
• checkState()
• checkValue()

• IndexOutOfBoundsException
• NullPointerException
• IllegalStateException

Instead of writing

    if ($count <= 0) {
        throw new \InvalidArgumentException("must be positive: " . $count);
    }

you could use a precondition like

    use \MehrAlsNix\Preconditions\PreconditionUtil;
    //...
    PreconditionUtil::checkArgument($count <= 0, 'must be positive: %s', $count);