First idea implementation

bukkit-helper/src/main/java/org/dynmap/bukkit/helper/BukkitVersionHelper.java

@@ -34,6 +34,10 @@ public abstract class BukkitVersionHelper {
     protected BukkitVersionHelper() {
         
     }
+    /**
+     * Get if it's unsafe to load chunks async
+     */
+    public abstract boolean isUnsafeAsync();
     /**
      * Get list of defined biomebase objects
      */

bukkit-helper/src/main/java/org/dynmap/bukkit/helper/BukkitVersionHelperCB.java

@@ -54,6 +54,12 @@ public class BukkitVersionHelperCB extends BukkitVersionHelperGeneric {
         isBadUnload = HDBlockModels.checkVersionRange(mcver, "1.9-");
         Log.verboseinfo("MCVER=" + mcver + ", isBadUnload=" + isBadUnload);
     }
+
+    @Override
+    public boolean isUnsafeAsync() {
+        return true;
+    }
+
     @Override
     protected String getNMSPackage() {
         Server srv = Bukkit.getServer();

bukkit-helper/src/main/java/org/dynmap/bukkit/helper/BukkitVersionHelperGlowstone.java

@@ -32,7 +32,12 @@ public class BukkitVersionHelperGlowstone extends BukkitVersionHelper {
             throw new IllegalArgumentException("Error initializing dynmap - Glowstone version incompatible!");
         }
     }
-    
+
+    @Override
+    public boolean isUnsafeAsync() {
+        return true;
+    }
+
     @Override
     public Object[] getBiomeBaseList() {
         return new Object[0];