presto-cli/src/main/java/io/prestosql/cli/AbstractWarningsPrinter.java/AbstractWarningsPrinter/printWithInitialSeparator
class AbstractWarningsPrinter:    private void printWithInitialSeparator(List<String> warnings)
    {
        // Separate first warnings from previous output
        if (!hasProcessedWarnings && !warnings.isEmpty()) {
            printSeparator();
            hasProcessedWarnings = true;
            print(warnings);
        }
    }