Fix mark support with buffering

SpigotCore_18/src/de/steamwar/core/WorldEditWrapper18.java

@@ -25,6 +25,7 @@ import com.sk89q.worldedit.extent.clipboard.Clipboard;
 import com.sk89q.worldedit.extent.clipboard.io.MCEditSchematicReader;
 import de.steamwar.sql.NoClipboardException;
 
+import java.io.BufferedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
@@ -34,7 +35,7 @@ public class WorldEditWrapper18 extends WorldEditWrapper14 {
     @SuppressWarnings("removal")
     public Clipboard getClipboard(InputStream is, boolean schemFormat) throws IOException {
         //Use FAWE reader due to FAWE capability of reading corrupt FAWE schems
-        NBTInputStream nbtStream = new NBTInputStream(is);
+        NBTInputStream nbtStream = new NBTInputStream(new BufferedInputStream(is));
         try {
             return (schemFormat ? new FastSchematicReader(nbtStream) : new MCEditSchematicReader(nbtStream)).read();
         } catch (NullPointerException e) {