module Header : sig ... endtype t = | Hello of Packet.bytes| ErrorMsg of Error.t| EchoRequest of Packet.bytes| EchoReply of Packet.bytes| VendorMsg of Vendor.t| SwitchFeaturesRequest| SwitchFeaturesReply of SwitchFeatures.t| FlowModMsg of FlowMod.t| PacketInMsg of PacketIn.t| FlowRemovedMsg of FlowRemoved.t| PortStatusMsg of PortStatus.t| PacketOutMsg of PacketOut.t| BarrierRequest| BarrierReply| StatsRequestMsg of StatsRequest.t| StatsReplyMsg of StatsReply.t| SetConfig of SwitchConfig.t| ConfigRequestMsg| ConfigReplyMsg of ConfigReply.tval size_of : t -> intval to_string : t -> string