awaitility/src/main/java/org/awaitility/pollinterval/IterativePollInterval.java
public static IterativePollInterval iterative(Function<Duration, Duration> function, Duration startDuration) {
        return new IterativePollInterval(function, startDuration);
    }
public static IterativePollInterval iterative(Function<Duration, Duration> function, Duration startDuration) {
        return new IterativePollInterval(function, startDuration);
    }
Syntactic sugar for creating a {@link IterativePollInterval}.

@param function      The function to use
@param startDuration The start duration (initial function value)
@return A new instance of {@link IterativePollInterval}