def debug(message = nil, ex = nil, data = nil, &block)
      log(DEBUG, message, ex, data, block)
    end
def debug(message = nil, ex = nil, data = nil, &block)
      log(DEBUG, message, ex, data, block)
    end
Log any one or more of a message, an exception and structured data as DEBUG.
 If the block is given for delay evaluation, it returns them as an array or the one of them as a value.
 @param message [String] The message to log. Use default_message if not specified.
 @param ex [Exception] The exception or the error
 @param data [Object] Any structured data
 @yieldreturn [String|Exception|Object|Array] Any one or more of former parameters
 @return [Boolean] true