private void WriteTerm(Term term)
{
int start = StringHelper.StringDifference(lastTerm.text, term.text);
int length = term.text.Length - start;
output.WriteVInt(start); // write shared prefix length
output.WriteVInt(length); // write delta length
output.WriteChars(term.text, start, length); // write delta chars
output.WriteVInt(fieldInfos.FieldNumber(term.field)); // write Field num
lastTerm = term;
}