# Pastebin wSVw7lV1
  fun ref received(conn: TCPConnection ref, data: Array[U8] iso) =>
    if _header then
      // code we wrote to turn the bytes into int
      let expect = Bytes.to_u32(data(0), data(1), data(2), data(3)).usize()

      conn.expect(expect)
      _header = false
    else
      // do something

      conn.expect(4)
      _header = true
    end