Refactor/2026 03 changing how result set data is stored

[takapi327]

Implementation Details

Refactored the design to change the internal data storage format of the ResultSet from decoded strings (Array[Option[String]]) to raw byte arrays (Array[Byte]), with decoding performed lazily when get*() methods are called.

In the previous implementation, when receiving row data from the MySQL server, the values of all columns were converted to the String type and stored. This approach had the following issues:

• Memory efficiency: Although the binary protocol does not require intermediate string conversion, all columns were being converted to strings.
• Unnecessary conversion overhead: When retrieving numeric values using getInt() or similar functions, a double conversion occurred: byte → string → numeric.
• Duplication between Text and Binary protocols: Different decoding logic was scattered across both protocols.

Pull Request Checklist

• Wrote unit and integration tests
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code formatting by scalafmt (sbt scalafmtAll command execution)
• Add copyright headers to new files

References