presto-parquet/src/main/java/io/prestosql/parquet/reader/TimestampMicrosColumnReader.java/TimestampMicrosColumnReader/readValue
class TimestampMicrosColumnReader:    @Override
    protected void readValue(BlockBuilder blockBuilder, Type type)
    {
        if (definitionLevel == columnDescriptor.getMaxDefinitionLevel()) {
            long utcMillis = MICROSECONDS.toMillis(valuesReader.readLong());
            // TODO: specialize the class at creation time
            if (type instanceof TimestampWithTimeZoneType) {
                type.writeLong(blockBuilder, packDateTimeWithZone(utcMillis, UTC_KEY));
            }
            else {
                type.writeLong(blockBuilder, utcMillis);
            }
        }
        else if (isValueNull()) {
            blockBuilder.appendNull();
        }
    }