MongoDB.Driver.Builders.MapReduceOptionsBuilder.SetFinalize C# (CSharp) Method

        public MapReduceOptionsBuilder SetFinalize(BsonJavaScript finalize)
        {
            _document["finalize"] = finalize;
            return this;
        }

        public void DoMapReduce()
        {
            string map = @"
                function() {
                    var logEntry = this;
                    emit(logEntry.Country, { count: 1, size: logEntry.Size });
                }";

            string reduce = @"
                function(key, values) {
                    var result = {count: 0, size: 0 };

                    values.forEach(function(value){
                        result.count += value.count;
                        result.size += value.size;
                    });

                    return result;
                }";

            string finalize = @"
                function(key, value){

                  value.averageSize = value.size / value.count;
                  return value;
                }";

            var collection = database.GetCollection(CollectionName);
            var options = new MapReduceOptionsBuilder();
            options.SetFinalize(finalize);
            options.SetOutput(MapReduceOutput.Inline);
            var results = collection.MapReduce(map, reduce, options);

            foreach (var result in results.GetResults())
            {
                Console.WriteLine(result.ToJson());
            }
        }