code: public String toHexString() {
  		byte[] bytes = this.data.array();
  		char[] hex = new char[this.data.remaining() * 2];
  		for (int i = this.data.position(); i < this.data.remaining(); i++) {
  			int b = bytes[i] & 0xFF;
  			hex[i * 2] = HEX_CHARS[b >>> 4];
  			hex[i * 2 + 1] = HEX_CHARS[b & 0x0F];
  		}
  		return new String(hex);
  	}
docs: Return the payload as a hexadecimal string.
  @return the payload as a hex string