This class models Quic Initial Packets, as defined by RFC 9000, Section 17.2.2:

An Initial packet uses long headers with a type value of 0x00.
   It carries the first CRYPTO frames sent by the client and server to perform
   key exchange, and it carries ACK frames in either direction.

   Initial Packet {
     Header Form (1) = 1,
     Fixed Bit (1) = 1,
     Long Packet Type (2) = 0,
     Reserved Bits (2),         # Protected
     Packet Number Length (2),  # Protected
     Version (32),
     DCID Len (8),
     Destination Connection ID (0..160),
     SCID Len (8),
     Source Connection ID (0..160),
     Token Length (i),
     Token (..),
     Length (i),
     Packet Number (8..32),     # Protected
     # Protected Packet Payload (..)
     Protected Payload (0..24), # Skipped Part
     Protected Payload (128),   # Sampled Part
     Protected Payload (..)     # Remainder
   }

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 Initial Packet structure than Quic Version 1, but uses a different long packet type than that shown above. See RFC 9369, Section 3.2.