presto-main/src/main/java/io/prestosql/util/JsonUtil.java/ArrayJsonGeneratorWriter/writeJsonValue
class ArrayJsonGeneratorWriter:        @Override
        public void writeJsonValue(JsonGenerator jsonGenerator, Block block, int position, ConnectorSession session)
                throws IOException
        {
            if (block.isNull(position)) {
                jsonGenerator.writeNull();
            }
            else {
                Block arrayBlock = type.getObject(block, position);
                jsonGenerator.writeStartArray();
                for (int i = 0; i < arrayBlock.getPositionCount(); i++) {
                    elementWriter.writeJsonValue(jsonGenerator, arrayBlock, i, session);
                }
                jsonGenerator.writeEndArray();
            }
        }