Why no small string tag?

[stephenberry]

Messages could be a byte smaller for small strings up to a length of 30 (n < 31). Why isn't this included?

• This string length compression would require a runtime branch. This has performance affects and makes the binary executable larger.
• It complicates the specification. A more complex specification makes it more difficult to implement and debug.
• This small string optimization does not apply to object keys or strings in arrays, which already omit the header.
• For applications where size is critical, the message is best compressed with an algorithm like LZ4, Brotli, or Zstandard. Compressing in this manner will often eliminate this extra byte.