code: public void fromBytes(byte[] data) {
          if (data == null || data.length != 4) {
              throw new IllegalArgumentException("invalid header data. It can't be null and the length must be 4 byte.");
          }
          this.packetBodyLength = (data[0] & 0xFF) | ((data[1] & 0xFF) << 8) | ((data[2] & 0xFF) << 16);
          this.setPacketSequenceNumber(data[3]);
      }
docs: little-endian byte order