public static void e(String msg, Throwable tr) {
        checkInitialization();
        sLogger.e(msg, tr);
    }
Log a message and a throwable with level {@link LogLevel#ERROR}.

@param msg the message to log
@param tr  the throwable to be log
android/android_framework/base/src/main/java/com/elvishew/xlog/XLog.java