seekExact
Attempts to seek to the exact term, returning true if the term is found. If this returns false, the enum is unpositioned. For some codecs, seekExact may be substantially faster than .seekCeil.
Return
true if the term is found; return false if the enum is unpositioned.
Seeks to the specified term by ordinal (position) as previously returned by .ord. The target ord may be before or after the current ord, and must be within bounds.