Collator strength value. When set, all differences are considered significant during comparison. The assignment of strengths to language features is locale dependant. A common example is for control characters ("\u0001" vs "\u0002") to be considered equal at the PRIMARY, SECONDARY, and TERTIARY levels but different at the IDENTICAL level. Additionally, differences between pre-composed accents such as "\u00C0" (A-grave) and combining accents such as "A\u0300" (A, combining-grave) will be considered significant at the IDENTICAL level if decomposition is set to NO_DECOMPOSITION.