presto-main/src/main/java/io/prestosql/operator/JoinProbe.java/JoinProbe/JoinProbeFactory
class JoinProbe:        public JoinProbeFactory(int[] probeOutputChannels, List<Integer> probeJoinChannels, OptionalInt probeHashChannel)
        {
            this.probeOutputChannels = probeOutputChannels;
            this.probeJoinChannels = probeJoinChannels;
            this.probeHashChannel = probeHashChannel;
        }