ZSTD_getSequenceLength
const ZSTD_SequenceLength seqLength = ZSTD_getSequenceLength(seqStore, seq);
const ZSTD_SequenceLength seqLen = ZSTD_getSequenceLength(seqStore, sequences+n);
total += ZSTD_getSequenceLength(seqStore, sp+n).litLength;
ZSTD_updateRep(rep.rep, seq->offBase, ZSTD_getSequenceLength(seqStorePtr, seq).litLength == 0);