Add helper method to OnDatapackSyncEvent (#9901)

Co-authored-by: blockingHD <9372035+blockinghd@users.noreply.github.com>

src/main/java/net/minecraftforge/event/OnDatapackSyncEvent.java

@@ -10,19 +10,20 @@ import net.minecraft.server.players.PlayerList;
 import net.minecraftforge.eventbus.api.Event;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.List;
+
 /**
  * Fires when a player joins the server or when the reload command is ran,
  * before tags and crafting recipes are sent to the client. Send datapack data
  * to clients when this event fires.
  */
-public class OnDatapackSyncEvent extends Event
-{
+public class OnDatapackSyncEvent extends Event {
     private final PlayerList playerList;
+
     @Nullable
     private final ServerPlayer player;
 
-    public OnDatapackSyncEvent(PlayerList playerList, @Nullable ServerPlayer player)
-    {
+    public OnDatapackSyncEvent(PlayerList playerList, @Nullable ServerPlayer player) {
         this.playerList = playerList;
         this.player = player;
     }
@@ -30,8 +31,7 @@ public class OnDatapackSyncEvent extends Event
     /**
      * @return The server's player list to get a view of all players.
      */
-    public PlayerList getPlayerList()
-    {
+    public PlayerList getPlayerList() {
         return this.playerList;
     }
 
@@ -40,8 +40,15 @@ public class OnDatapackSyncEvent extends Event
      *         such as when the reload command runs.
      */
     @Nullable
-    public ServerPlayer getPlayer()
-    {
+    public ServerPlayer getPlayer() {
         return this.player;
     }
+
+    /**
+     * @return A list of players that should receive data during this event, which is the specified player (if not null)
+     *         or all players otherwise.
+     */
+    public List<ServerPlayer> getPlayers() {
+        return this.player == null ? this.playerList.getPlayers() : List.of(this.player);
+    }
 }