Add throwable parameter to Log.w()

When an exception occurs, we might want to log a warning instead of an
error.

PR #2802 <#2802>

server/src/main/java/com/genymobile/scrcpy/Ln.java

@@ -57,13 +57,20 @@ public static void i(String message) {
         }
     }
 
-    public static void w(String message) {
+    public static void w(String message, Throwable throwable) {
         if (isEnabled(Level.WARN)) {
-            Log.w(TAG, message);
+            Log.w(TAG, message, throwable);
             System.out.println(PREFIX + "WARN: " + message);
+            if (throwable != null) {
+                throwable.printStackTrace();
+            }
         }
     }
 
+    public static void w(String message) {
+        w(message, null);
+    }
+
     public static void e(String message, Throwable throwable) {
         if (isEnabled(Level.ERROR)) {
             Log.e(TAG, message, throwable);