// convert n to digit string in buffer, return length of string
uint32_t util64_tou(int64_t n, UChar* buffer, uint32_t buflen, uint32_t radix = 10, UBool raw = FALSE);
// convert n to digit string in buffer, return length of string
uint32_t util64_tou(int64_t n, UChar* buffer, uint32_t buflen, uint32_t radix = 10, UBool raw = FALSE);