presto-main/src/main/java/io/prestosql/operator/scalar/MapEntriesFunction.java/MapEntriesFunction/MapEntriesFunction
class MapEntriesFunction:    @TypeParameter("K")
    @TypeParameter("V")
    public MapEntriesFunction(@TypeParameter("array(row(K,V))") Type arrayType)
    {
        pageBuilder = new PageBuilder(ImmutableList.of(arrayType));
    }