code: public long nzNumber(ImapRequestLineReader request) throws ProtocolException {
          long number = number(request);
          if (number == 0) {
              throw new ProtocolException("Zero value not permitted.");
          }
          return number;
      }
docs: Reads an argument of type "nznumber" (a non-zero number)
  (NOTE this isn't strictly as per the spec, since the spec disallows
  numbers such as "0123" as nzNumbers (although it's ok as a "number".
  I think the spec is a bit shonky.)