Flush clipboards before writing schematics.

#1286

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

@@ -72,6 +72,7 @@ public class FastSchematicWriter implements ClipboardWriter {
 
     @Override
     public void write(Clipboard clipboard) throws IOException {
+        clipboard.flush();
         // For now always write the latest version. Maybe provide support for earlier if more appear.
         write2(clipboard);
     }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/clipboard/io/schematic/MinecraftStructure.java

@@ -153,6 +153,7 @@ public class MinecraftStructure implements ClipboardReader, ClipboardWriter {
 
     @Override
     public void write(Clipboard clipboard) throws IOException {
+        clipboard.flush();
         write(clipboard, "FAWE");
     }
 

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/clipboard/io/schematic/PNGWriter.java

@@ -31,6 +31,7 @@ public class PNGWriter implements ClipboardWriter {
 
     @Override
     public void write(Clipboard clipboard) throws IOException {
+        clipboard.flush();
         Region region = clipboard.getRegion();
         int width = region.getWidth();
         int height = region.getHeight();