Use separate thread to send packets, even in sync mode (fixes #674)

src/main/java/com/replaymod/replay/QuickReplaySender.java

@@ -137,13 +137,13 @@ public class QuickReplaySender extends ChannelHandlerAdapter implements ReplaySe
                 LOGGER.info("Initialized quick replay sender in " + (System.currentTimeMillis() - start) + "ms");
             } catch (Throwable e) {
                 LOGGER.error("Initializing quick replay sender:", e);
-                mod.getCore().runLater(() -> {
+                mod.getCore().runLaterWithoutLock(() -> {
                     mod.getCore().printWarningToChat("Error initializing quick replay sender: %s", e.getLocalizedMessage());
                     promise.setException(e);
                 });
                 return;
             }
-            mod.getCore().runLater(() -> promise.set(null));
+            mod.getCore().runLaterWithoutLock(() -> promise.set(null));
         }).start();
         return promise;
     }