Make clipboard flushable

#1286

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/clipboard/LinearClipboard.java

@@ -49,9 +49,6 @@ public abstract class LinearClipboard extends SimpleClipboard {
 
     public abstract Collection<CompoundTag> getTileEntities();
 
-    public void flush() {
-    }
-
     @Override
     protected void finalize() {
         close();

worldedit-core/src/main/java/com/sk89q/worldedit/extent/clipboard/BlockArrayClipboard.java

@@ -323,6 +323,11 @@ public class BlockArrayClipboard implements Clipboard {
         this.parent.close();
     }
 
+    @Override
+    public void flush() {
+        this.parent.flush();
+    }
+
     //FAWE start
 
     /**

worldedit-core/src/main/java/com/sk89q/worldedit/extent/clipboard/Clipboard.java

@@ -52,6 +52,7 @@ import javax.annotation.Nullable;
 import java.io.Closeable;
 import java.io.File;
 import java.io.FileOutputStream;
+import java.io.Flushable;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.net.URI;
@@ -63,7 +64,9 @@ import static com.google.common.base.Preconditions.checkNotNull;
 /**
  * Specifies an object that implements something suitable as a "clipboard."
  */
-public interface Clipboard extends Extent, Iterable<BlockVector3>, Closeable {
+//FAWE start - Iterable, closeable and flushable
+public interface Clipboard extends Extent, Iterable<BlockVector3>, Closeable, Flushable {
+    //FAWE end
 
     //FAWE start
     static Clipboard create(Region region) {
@@ -187,6 +190,10 @@ public interface Clipboard extends Extent, Iterable<BlockVector3>, Closeable {
     default void close() {
     }
 
+    @Override
+    default void flush() {
+    }
+
     /**
      * Forwards to {@link #paste(World, BlockVector3, boolean, boolean, Transform)}.
      */