public static void d(String tag, String msg, Throwable tr) {
        println(DEBUG, tag, msg, tr);
    }
Prints a message at DEBUG priority.

@param tag Tag for for the log data. Can be used to organize log statements.
@param msg The actual message to be logged.
@param tr If an exception was thrown, this can be sent along for the logging facilities
          to extract and print useful information.
SwipeRefreshMultipleViews/Application/src/main/java/com/example/android/common/logger/Log.java