The code unit index in the original input string at which the segment begins.
The complete input string that was segmented.
A boolean value only if granularity is "word"; otherwise, undefined. If granularity is "word", then isWordLike is true when the segment is word-like (i.e., consists of letters/numbers/ideographs/etc.); otherwise, false.
A string containing the segment extracted from the original input string.