public void setCoolDown(final TimeValue coolDown) {
        Args.notNull(coolDown, "Cool down time value cannot be null");
        Args.positive(coolDown.getDuration(), "coolDown");
        this.coolDown.set(coolDown);
    }
Sets the cool-down time value for adjustments in pool sizes for a given host. This time value
allows enough time for the adjustments to take effect before further adjustments are made.
The cool-down time value must be positive and not null.

@param coolDown the TimeValue representing the cool-down period between adjustments
@throws IllegalArgumentException if the provided cool-down time value is null or non-positive
httpclient5/src/main/java/org/apache/hc/client5/http/impl/classic/AbstractBackoff.java