presto-main/src/main/java/io/prestosql/sql/planner/LocalDynamicFilter.java/LocalDynamicFilter/LocalDynamicFilter
class LocalDynamicFilter:    public LocalDynamicFilter(Multimap<String, Symbol> probeSymbols, Map<String, Integer> buildChannels, int partitionCount)
    {
        this.probeSymbols = requireNonNull(probeSymbols, "probeSymbols is null");
        this.buildChannels = requireNonNull(buildChannels, "buildChannels is null");
        verify(probeSymbols.keySet().equals(buildChannels.keySet()), "probeSymbols and buildChannels must have same keys");

        this.resultFuture = SettableFuture.create();

        this.result = TupleDomain.none();
        this.partitionsLeft = partitionCount;
    }