code: public void setDelimiter(byte[] delim, boolean resetMatchCount) {
          if (delim == null) {
              throw new NullPointerException("Null delimiter not allowed");
          }
  
          // Convert delimiter to IoBuffer.
          IoBuffer delimiter = IoBuffer.allocate(delim.length);
          delimiter.put(delim);
          delimiter.flip();
  
          ctx.setDelimiter(delimiter);
          ctx.setContentLength(-1);
          if (resetMatchCount) {
              ctx.setMatchCount(0);
          }
      }
docs: Dynamically sets a new delimiter. Next time
  {@link IoBufferDecoder#decodeOnce(IoSession, int) } will be called it will use the new
  delimiter. Delimiter matching is reset only if <tt>resetMatchCount</tt> is true but
  decoding will continue from current position.
  
  NB : Delimiter {@link LineDelimiter#AUTO} is not allowed.
  
  @param delim the new delimiter as a byte array
  @param resetMatchCount delimiter matching is reset if true