title: How to combine CRC-32 results?
body: <p>Let's say I have two numbers X = 0xABC; Y = 0xDE.
  I want to calculate CRC-32 over Z, which is X concatenated to Y i.e. Z = 0xABCDE.</p>
  
  <p>I have CRC(X) and CRC(Y) available. How can I compute CRC(Z) ?</p>