Function execute_code_units 

pub fn execute_code_units<E>(
    automaton: &Automaton<u16, E>,
    subject: &CodeUnitString,
    limits: TextLimits,
    extension_matches: impl Fn(&E, &u16) -> bool,
) -> DomainExecutionOutcome<CodeUnitDomain>

Execute a code-unit-domain automaton over an exact sim-text value.

Unlike scalar execution, every position between adjacent u16 values is addressable, including the middle of a surrogate pair and either side of a lone surrogate.

use sim_lib_pattern::{CodeUnitOffset, ScalarOffset, require_code_unit_offset};
require_code_unit_offset(ScalarOffset::new(1));