title: how to use scapy to decode H2C message
body: <p>scapy has a module named http2, and in its information: "encode/decode HTTP/2 Frames"</p>
  
  <pre class="lang-py prettyprint-override"><code>import scapy.contrib.http2 as http2
  packets = rdpcap("in.pcapng")
  for p in packets:
      if p.haslayer(TCP):
          p[TCP].payload # how to turn this into a http2.H2Seq or http2.H2Frame??
  </code></pre>
  
  <p><code>p[TCP].payload.name</code> gives "raw", and <code>p.haslayer(http2.H2Seq)</code> or <code>http2.H2Frame</code> gives false. </p>
  
  <p>I would like to turn this packet into a http2 one, and then parse headers or data if any.</p>