docs: private void nextStep(byte[] buf, int toWrite, Runnable next, boolean newMsgFlag)
      {
          if (buf != null) {
              writeBuf = ByteBuffer.wrap(buf);
              writeBuf.limit(toWrite);
          }
          else {
              writeBuf = null;
          }
          this.toWrite = toWrite;
          this.next = next;
          this.newMsgFlag = newMsgFlag;
      }