@Override
    protected void doExecute(ExecutionContext context) {
        FieldValue value = context.getCurrentValue();
        if (value instanceof NumericFieldValue num) {
            double napSecs = num.getNumber().doubleValue();
            long nanos = (long)(napSecs*1_000_000_000.0);
            try {
                Thread.sleep(nanos / 1_000_000, (int) (nanos % 1_000_000));
            } catch (InterruptedException e) {
                // Do nothing
            }
        }
    }
Utility expression that will sleep the amount of time given in the numeric field.
Non-numeric fields will be ignored.

@author baldersheim
indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/SleepExpression.java