fact: Definition must {A} (x: option A) (pr: IsSome x) : A := match x as xx return (IsSome xx -> A) with | Some a => fun _ => a | None => fun pr => False_rect _ pr end pr.
imports: Bedrock.Word Fiat.Narcissus.Examples.NetworkStack.EthernetHeader Fiat.Narcissus.Examples.NetworkStack.ARPPacket Fiat.Narcissus.Examples.NetworkStack.IPv4Header Fiat.Narcissus.Examples.NetworkStack.TCP_Packet Fiat.Narcissus.Examples.NetworkStack.UDP_Packet AlignedByteString