Async Operation Catching

Catch and throw an exception when a potentially unsafe operation occurs on a thread other than the main server thread.

By: md_5 <git@md-5.net>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -898,6 +898,7 @@ public final class CraftServer implements Server {
     public boolean dispatchCommand(CommandSender sender, String commandLine) {
         Preconditions.checkArgument(sender != null, "sender cannot be null");
         Preconditions.checkArgument(commandLine != null, "commandLine cannot be null");
+        org.spigotmc.AsyncCatcher.catchOp("command dispatch"); // Spigot
 
         if (this.commandMap.dispatch(sender, commandLine)) {
             return true;