public static void d(String tag, String msg, Object arg1, Object arg2, Object arg3, Object arg4) {
    if (sHandler.isLoggable(DEBUG)) {
      sHandler.d(tag, formatString(msg, arg1, arg2, arg3, arg4));
    }
  }
Sets the logging delegate that overrides the default delegate.

@param delegate the delegate to use
fbcore/src/main/java/com/facebook/common/logging/FLog.java