public static void w(String tag, String msg, Throwable throwable) {
        if (sLevel > LEVEL_WARNING) {
            return;
        }
        Log.w(tag, msg, throwable);
    }
Send a WARNING log message

@param tag
@param msg
@param throwable
ptr-lib/src/in/srain/cube/views/ptr/util/PtrCLog.java