initial work on UnuseItemMessage packet

common/src/main/scala/net/psforever/packet/GamePacketOpcode.scala

@@ -363,7 +363,7 @@ object GamePacketOpcode extends Enumeration {
     case 0x23 => noDecoder(ActionCancelAcknowledgeMessage)
     case 0x24 => game.SetEmpireMessage.decode
     case 0x25 => game.EmoteMsg.decode
-    case 0x26 => noDecoder(UnuseItemMessage)
+    case 0x26 => game.UnuseItemMessage.decode
     case 0x27 => game.ObjectDetachMessage.decode
     // 0x28
     case 0x28 => game.CreateShortcutMessage.decode

common/src/main/scala/net/psforever/packet/game/UnuseItemMessage.scala

@@ -0,0 +1,25 @@
+// Copyright (c) 2017 PSForever
+package net.psforever.packet.game
+
+import net.psforever.packet.{GamePacketOpcode, Marshallable, PlanetSideGamePacket}
+import scodec.Codec
+import scodec.codecs._
+
+/**
+  * Dispatched by the client when its player is done using something.
+  * The classic example is sifting through backpacks, an exclusive activity that only one player can do at a time.
+  */
+final case class UnuseItemMessage(guid1 : PlanetSideGUID,
+                                  guid2 : PlanetSideGUID)
+  extends PlanetSideGamePacket {
+  type Packet = UnuseItemMessage
+  def opcode = GamePacketOpcode.UnuseItemMessage
+  def encode = UnuseItemMessage.encode(this)
+}
+
+object UnuseItemMessage extends Marshallable[UnuseItemMessage] {
+  implicit val codec : Codec[UnuseItemMessage] = (
+    ("guid1" | PlanetSideGUID.codec) ::
+      ("guid2" | PlanetSideGUID.codec)
+    ).as[UnuseItemMessage]
+}