presto-main/src/main/java/io/prestosql/operator/OperatorStats.java/OperatorStats/mergeInfo
class OperatorStats:    @SuppressWarnings("unchecked")
    private static <T> Mergeable<T> mergeInfo(Mergeable<T> base, T other)
    {
        return (Mergeable<T>) base.mergeWith(other);
    }