code: public byte[] sendBindResp(OutputStream os, int commandId,
              int sequenceNumber, String systemId, InterfaceVersion interfaceVersion) throws PDUStringException,
              IOException {
          synchronized (os) {
              return pduSender.sendBindResp(os, commandId, sequenceNumber,
                      systemId, interfaceVersion);
          }
      }
docs: /*
  (non-Javadoc)
  
  @see org.jsmpp.PDUSender#sendBindResp(java.io.OutputStream, int, int,
  java.lang.String)