@Override
  public void prepare() throws IOException {
    if (handshakeStartTime == -1) {
      handshakeStartTime = time.milliseconds();
    }
    if (!ready()) {
      handshake();
    }
  }
Prepares the channel to accept read or write. We do handshake if not yet complete
@throws IOException
ambry-network/src/main/java/com/github/ambry/network/SSLTransmission.java