public static void log(int logLevel, String msg, Throwable tr) {
    assertInitialization();
    sLogger.log(logLevel, msg, tr);
  }
Log a message and a throwable with specific log level.

@param logLevel the specific log level
@param msg      the message to log
@param tr       the throwable to be log
@since 1.4.0
xlog/src/main/java/com/elvishew/xlog/XLog.java