presto-record-decoder/src/main/java/io/prestosql/decoder/raw/RawColumnDecoder.java/RawValueProvider/getDouble
class RawValueProvider:        @Override
        public double getDouble()
        {
            checkEnoughBytes();
            switch (fieldType) {
                case FLOAT:
                    return value.getFloat();
                case DOUBLE:
                    return value.getDouble();
                default:
                    throw new PrestoException(DECODER_CONVERSION_NOT_SUPPORTED, format("conversion '%s' to double not supported", fieldType));
            }
        }