Be aware some features will not work with variable length utf-8 #185

Important Limitation
SDS does NOT provide UTF-8-aware character operations. For example:

sdslen() returns the byte length, not the character count
sdstrim() works on individual bytes, not UTF-8 grapheme clusters
sdstoupper() and sdstolower() use toupper()/tolower() on individual bytes (lines 783-794), which won't work correctly for UTF-8.