This class models Quic 0-RTT Packets, as defined by RFC 9000, Section 17.2.3:

A 0-RTT packet uses long headers with a type value of 0x01, followed
   by the Length and Packet Number fields; see Section 17.2. The first
   byte contains the Reserved and Packet Number Length bits; see Section 17.2.
   A 0-RTT packet is used to carry "early" data from the client to the server
   as part of the first flight, prior to handshake completion. As part of the
   TLS handshake, the server can accept or reject this early data.

   See Section 2.3 of [TLS13] for a discussion of 0-RTT data and its limitations.

   0-RTT Packet {
     Header Form (1) = 1,
     Fixed Bit (1) = 1,
     Long Packet Type (2) = 1,
     Reserved Bits (2),
     Packet Number Length (2),
     Version (32),
     Destination Connection ID Length (8),
     Destination Connection ID (0..160),
     Source Connection ID Length (8),
     Source Connection ID (0..160),
     Length (i),
     Packet Number (8..32),
     Packet Payload (..),
   }
 

Subclasses of this class may be used to model packets exchanged with either Quic Version 1 or Quic Version 2. Note that Quic Version 2 uses the same 0-RTT Packet structure than Quic Version 1, but uses a different long packet type than that shown above. See RFC 9369, Section 3.2.